UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station 


BULLETIN  No.  317 


RELATIVE  ENERGY  VALUE  OF 

ALFALFA,  CLOVER,  AND  TIMOTHY  HAY 

FOR  THE  MAINTENANCE  OF  SHEEP 


By  H.  H.  MITCHELL,  W.  G.  KAMMLADE, 
and  T.  S.  HAMILTON 


URBANA,  ILLINOIS,  DECEMBER,  1928 


CONTENTS 

Page 

FIRST  EXPERIMENT:    ALFALFA,  CLOVER,  AND  TIMOTHY  HAY. .  131 

Outline   of  Experiment 131 

The  Experimental  Data 132 

Body    Weights 132 

Digestibility  and  Energy  Content  of  Rations 134 

Feed  and  Metabolizable  Energy  Requirements  for  Maintenance 139 

Summary  of  the  First  Experiment 140 

Critical   Consideration 141 

SECOND  EXPERIMENT:    ALFALFA  AND  TIMOTHY  HAY 144 

Outline  of  Experiment 144 

Results  of  the  Second  Experiment 146 

Chemical  Composition  of  the  Check  Sheep 146 

Feeding  Period  and  Changes  in  Body  Weight 150 

Amount  and  Composition  of  Wool  Sheared  at  End  of  Period  1 151 

Digestibility  and  Metabolizable  Energy  Content  of  Rations 151 

Nitrogen  Balances 154 

Chemical  Composition  of  Surviving  Sheep 154 

Growth  of  Wool  by  Sheep  on  a  Submaintenance  Ration 156 

Comparison  of  Composition  of  Tissues  From  Well-Fed  and 

From  Emaciated  Sheep 157 

Loss  of  Body  Constituents  During  Feeding  Period 158 

Feed  Consumption  and  Its  Content  of  Metabolizable  Energy 159 

Summary  of  the  Se-cond  Experiment 163 

Conclusions  of  the  Second   Experiment 167 


RELATIVE  ENERGY  VALUE 

OF  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR 
THE  MAINTENANCE  OF  SHEEP 

By  H.  H.  MITCHELL,  W.  G.  KAMMLADE  and  T.  S.  HAMILTON' 

The  method  in  most  common  use  of  measuring  the  value  of  dif- 
ferent feeds  as  sources  of  nutritive  energy  for  farm  animals  involves 
the  employment  of  average  values  of  the  total  digestible  nutrients. 
It  seems  clear,  however,  that  the  determination  of  the  digestible  or- 
ganic matter  of  a  feed,  even  when  allowance  is  made  for  the  differ- 
ences in  metabolizable  energy  among  the  individual  nutrients,  can 
give  no  certain  information  as  to  the  utilization  of  the  digestible  ma- 
terial in  metabolism. 

There  are  two  important  objections  to  the  use  of  values  for  the 
total  digestible  nutrients  of  feeds  as  measures  of  their  content  of 
nutritive  energy,  i.e.,  food  energy  available  for  expenditure  in  main- 
tenance or  work,  or  for  storage  in  the  tissues  or  secretion  in  the  milk. 
The  first  objection  relates  to  the  fact  that  the  calculation  of  such 
values  is  based  on  the  assumption  that  the  difference  between  the 
amounts  of  nutrients  consumed  and  the  amounts  of  nutrients  appear- 
ing in  the  feces  represents  those  fractions  which  are  available  to  the 
animal  for  maintenance  and  production.  In  the  case  of  nonrumi- 
nants  this  assumption  may  be  roughly  true,  but  in  the  case  of  rumi- 
nants, in  which  extensive  fermentations  are  occurring  in  the  fore  part 
of  the  alimentary  tract,  considerable  amounts  of  gaseous  material  un- 
available to  the  animal  are  formed  and  considerable  amounts  of  heat 
representing  losses  in  nutritive  energy  are  being  produced.  These 
losses  of  matter  and  energy  cannot  be  determined  from  an  analysis 
of  the  feces,  and  yet  they  represent  losses  of  nutritive  energy  as  real 
as  the  energy  of  the  undigested  organic  constituents  of  the  feces.  This 
objection  has  been  developed  and  illustrated  by  Fries.2 

The  second  important  objection  to  the  use  of  the  total  digestible 
nutrients  of  feeds  as  measures  of  nutritive  energy  relates  to  the  fact 
that  large  losses  of  energy  occur  in  animals  during  the  digestion  and 
assimilation  of  feed,  these  losses  being  represented  by  increases  in 
the  heat  production  of  the  animal.  Regardless  of  the  causes  for  such 
losses  of  energy,  they  are  inevitable  and  therefore  must  relate  to  defi- 
nite physiological  processes  occurring  in  the  animal  body  consequent 


JH.  H.  MITCHELL,  Chief  in  Animal  Nutrition;  W.  G.  KAMMLADE,  Assistant  Chief  in  Sheep 
Husbandry;  and  T.  S.  HAMILTON,  Associate  in  Animal  Nutrition.  With  the  technical  assistance 
of  C.  H.  KICK. 

2Fries,  J.  A.  Digestibility  of  cattle  feed.     Amer.  Soc.  Anim.  Prod.  Proc.,  1922,  33. 

127 


128 


BULLETIN  No.  317 


[December, 


upon  the  digestion  of  feed,  its  absorption  into  the  blood  and  its  trans- 
position to  the  tissues.  This  increment  in  heat  production  is  not  avail- 
able for  maintenance  except  under  conditions  in  which  the  environ- 
mental temperature  is  lower  than  the  critical  temperature  of  the  fast- 
ing animal. 

The  net  energy  values  of  Armsby  are  complete  expressions  of 
the  actual  values  of  feeds  as  sources  of  nutritive  energy,  since  they 
are  obtained  by  deducting  from  the  gross  energy  of  the  feed  not  only 
the  gross  energy  of  the  feces,  but  also  the  energy  losses  due  to  gastro- 
intestinal fermentations,  to  incomplete  oxidations  in  the  body,  and 
to  the  stimulating  effect  of  feed  on  heat  production.  They  represent, 
therefore,  the  ultimate  net  return  to  the  animal  in  nutritive  energy 
resulting  from  the  consumption  of  the  feed. 

Altho  net  energy  values  represent  a  complete  scheme  of  evaluat- 
ing feeds  with  reference  only  to  their  content  of  nutritive  energy,  the 
total  digestible  nutrients  of  different  feeds  may  still  represent  their 
relative  energy  values  provided  that  the  losses  of  energy  not  con- 
sidered in  digestion  experiments  were  roughly  proportional  to  the 
content  of  total  digestible  nutrients;  in  other  words,  that  the  net  en- 
ergy value  per  pound  of  digestible  nutrients  was  practically  the  same 
for  different  feeds.  However,  the  calculations  contained  in  Table  1, 

TABLE  1. — ESTIMATED  NET  ENERGY  PER  POUND  OF  DIGESTIBLE  NUTRIENTS 
FOR  A  FEW  REPRESENTATIVE  FARM  FEEDS 


Feed 

Net  energy  per 
100  pounds1 

Digestible 
nutrients  per 
100  pounds2 

Net  energy  per 
pound  digestible 
nutrients 

therms 
43.02 

Ibs. 
48.5 

therms 

.887 

Alfalfa  hay  

34.23 

51.6 

.663 

38  68 

50  9 

.760 

34.81 

45.6 

.763 

15.90 

17.7 

.898 

Corn  

85.50 

85.7 

.998 

Oats 

67  56 

70.4 

.960 

Wheat 

91.82 

80.1 

1.146 

Wheat  bran  

53.00 

60.9 

.870 

Cottonseed  meal,  prime  

90.00 

75.5 

1.192 

Linseed  oil  meal,  old  process  

88.91 

77.9 

1.141 

JFrom  Armsby's  "Nutrition  of  Farm  Animals,"  1917.  2From  Henry  and  Morrison's  "Feeds  and 
Feeding,"  18th  ed.,  1923. 

of  a  few  commonly  used  roughages  and  concentrates,  indicate  that  the 
net  energy  value  per  pound  of  digestible  nutrients  varies  considerably 
for  different  feeds  and  in  general  is  lower  for  roughages  than  for  con- 
centrates. 

Attention  is  called  particularly  to  the  content  of  alfalfa,  clover, 
and  timothy  hay  in  total  digestible  nutrients  and  in  net  energy.  Ac- 
cording to  their  content  of  digestible  nutrients  these  three  hays  are 
very  nearly  equal  as  sources  of  nutritive  energy.  Taking  alfalfa  hay 
as  100  in  its  content  of  total  digestible  nutrients,  clover  hay  has  a 


1928] 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


129 


value  of  99  and  timothy  hay  a  value  of  94.  However,  according  to  the 
net  energy  calculations  of  Armsby,  based  upon  the  same  average  an- 
alyses of  the  hays  as  were  used  in  computing  their  content  of  total 
digestible  nutrients,  considerable  differences  in  their  content  of  nutri- 
tive energy  exist  among  them.  Taking  the  net  energy  content  of  al- 
falfa hay  as  100,  clover  hay  has  a  value  of  113  and  timothy  hay  a 
value  of  126.  The  net  energy  values  of  these  hays  have  been  recom- 
puted by  Forbes  and  Kriss.1  If  the  revised  net  energy  value  per  kilo- 
gram of  dry  matter  of  alfalfa  hay  be  taken  as  100,  the  revised  value 
for  clover  hay  becomes  106  and  that  for  timothy  hay  133. 

The  relatively  high  net  energy  value  of  timothy  hay  is  particu- 
larly noteworthy,  since  it  apparently  contradicts  the  current  belief  of 
the  superiority  of  alfalfa  over  timothy  hay.  The  contradiction  is, 
however,  only  apparent,  since  the  established  superiority  of  alfalfa 
over  timothy  hay  is  founded  upon  a  basis  other  than  its  content  of 
nutritive  energy.  Its  greater  palatability  for  most  classes  of  live- 
stock also  contributes  to  its  economic  superiority  over  timothy  hay. 

The  individual  experiments  of  Armsby  and  associates  relative  to 
the  utilization  of  the  energy  of  these  three  hays  are  summarized  in 
Tables  2,  3,  and  4.  In  these  calculations  the  original  figures  of  Arras- 

TABLE  2. — SUMMARY  OF  DETERMINATIONS  OF  UTILIZATION  OF  ENERGY  OF  ALFALFA 
HAY  BY  STEERS,  REPORTED  BY  ARMSBY  AND  ASSOCIATES 

(Energy  per  kilogram  of  dry  matter) 


Exp. 
No. 

Steer 
No. 

Gross 

Metabolizable 

Net  available 

Literature 
reference 

208... 

C 
D 
E 
F 
H 
H 
J 

cals. 
4  405 
4  407 
4  408 
4  338 
4  368 
4  374 
4  334 

4  376 

calf. 
1  820 
1  729 
1   837 
1   810 
2  056 
2  012 
1  945 

1  887 

pet.  of 
gross 
41.3 
39.2 

41.7 
41.8 
47.1 
46.0 
44.9 

43.1 

cals. 
684 
392 
635 
671 
1  017 
895 
927 

746 

pet.  of 
metab. 
37.6 
22.7 
34.6 
37.1 
411  .  5 
44.5 
47.7 

39.1 

J.  Agr.  Res.  3, 
435.     1915. 

Ibid.  18.  269. 
1918. 

208  

208 

209         .    . 

212  

212  

216     . 

Average..  .  . 

TABLE  3. — UTILIZATION  OF  ENERGY  OF  RED  CLOVER  HAY  BY  STEERS 
SUMMARY  OF  EXPERIMENTS  BY  ARMSBY  AND  ASSOCIATES 

(Energy  per  kilogram  of  dry  matter) 


Exp. 

No. 

Steer 
Xo. 

Gross 

Metabolizable 

Net  available 

Literature 
reference 

179... 

I 
I 
I 
K 

cals. 
4  438 
4  486 

4  '367 
4  430 

cals. 
1  926 
2  076 
2   127 
1  954 

2  021 

pet.  of 
gross 
43.4 
46.3 

44  '.7 
44.8 

cals. 
934 
1  651 
1  771 
1  Oil 

9731 

pet.  of 
metab. 
48.5 
79.5 
83.3 
51.7 

50.  11 

J.  Agr.  Res.  3, 
435.     1915. 

Ibid.  7,  379. 
1916. 

186a 

186b  

220  

Average..  .  . 

'Not  including  the  results  in  Experiment  186. 


'Forbes,  E.  B.,  and  Kriss,  M.     Revised  net  energy  values  of  feeding  stuffs 
for  cattle.    Jour.  Agr.  Res.  31.  1083.    1925. 


130 


BULLETIN  No.  317 


[December, 


TABLE  4. — UTILIZATION  OF  ENERGY  OF  TIMOTHY  HAY  BY  STEERS,  SUMMARY 
OF  EXPERIMENTS  BY  ARMSBY  AND  ASSOCIATES 

(Energy  per  kilogram  of  dry  matter) 


Exp. 
No. 

Steer 
No. 

Gross 

Metabolizable 

Net  available 

Literature 
reference 

190... 

A 
A 
A 
B 
B 
B 
I 

cats. 
4  495 
4  509 
4  515 
4  493 
4  509 
4  515 
4  483 

4  503 

cals. 
1  785 
1  835 
2  086 
1  844 
1  895 
2  036 
1  953 

1  919 

pet.  of 
gross 
39.7 
40.7 
46.2 
41.0 
42.0 
45.1 
43.6 

42.6 

cals. 
1  067 
1  306 
1  184 
922 
1   102 
1  082 
1  294 

1    137 

pet.  of 
metab. 
59.8 
71.2 
56.8 
50.0 
58.2 
53.1 
66.3 

'  61.5 

J.  Agr.  Res.  3, 
435.     1915. 

200  

207  

190  

200  

207  ... 

174  

Average.  . 

by  for  the  heat  production  of  the  steers  were  used  rather  than  the 
recalculations  of  Forbes  and  Kriss. 

Per  kilogram  of  dry  matter,  the  three  hays  are  closely  similar  in 
their  content  of  gross  and  metabolizable  energy.  The  slight  differ- 
ences between  the  average  figures  are  probably  not  significant.  How- 
ever, distinct  differences  appear  with  reference  to  their  net  energy 
content  per  kilogram  of  dry  matter,  particularly  if  the  results  of  Ex- 
periment 186  on  red-clover  hay  are  omitted.  Armsby  himself  was  in- 
clined to  disregard  this  experiment  in  the  computations  of  his  average 
results  on  the  basis  of  certain  unsatisfactory  experimental  conditions, 
while  Forbes  and  Kriss  (loc.  cit.)  have  definitely  discarded  it  in  their 
recomputations  of  Armsby's  work.  The  close  agreement  between  the 
much  lower  results  of  Experiments  179  and  220  may  be  taken  as  pro- 
visional justification  for  disregarding  the  results  of  Experiment  186, 
tho  evidently  the  situation  with  respect  to  the  net  energy  value  of  red- 
clover  hay  is  in  a  very  unsatisfactory  condition. 

These  experiments  indicate  clearly  that  the  metabolizable  energy 
of  timothy  hay  is  distinctly  better  utilized  by  steers  in  covering  their 
maintenance  requirement  for  energy  than  is  the  metabolizable  energy 
of  alfalfa  hay.  The  two  concordant  results  on  red-clover  hay  would 
indicate  that  it  occupies  an  intermediate  position  in  this  respect.  The 
average  percentage  utilization  of  the  metabolizable  energy  of  timothy 
hay  is  61.5,  of  red-clover  hay  50.1,  and  of  alfalfa  hay  39. 1.1  Forbes 
and  Kriss,  in  their  recomputations  and  reinterpretations  of  Armsby's 
work,  arrive  at  different  averages,  i.e.,  60.8  for  timothy,  49.6  for  clover, 
and  47.1  for  alfalfa,  bearing  the  same  relation  to  one  another,  how- 
ever. 


values  apply  only  from  an  approximate  maintenance  level  of  feeding 
to  one  permitting  moderate  fattening.  Forbes  and  associates  have  shown  that  at 
lower  levels  of  feeding,  the  metabolizable  energy  of  feeds  is  utilized  to  a  greater 
extent  (Forbes,  E.  B.,  Fries,  J.  A.,  Braman,  W.  W.,  and  Kriss,  M.  The  rela- 
tive utilization  of  feed  energy  for  maintenance,  body  increase  and  milk  produc- 
tion in  cattle.  Jour.  Agr.  Res.  33,  483.  1926.) 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOK  SHEKP  131 

The  considerable  difference  in  the  results  obtained  between  the 
two  most  common  methods  of  measuring  the  content  of  farm  feeds 
in  nutritive  energy  relative  to  the  values  for  these  three  common  hays, 
is  sufficient  justification  for  a  redetermination  of  the  value  of  these 
feeds  as  sources  of  energy  in  maintenance,  preferably  by  some  method 
different  from  that  heretofore  used.  Altho  the  net  energy  values  possess 
a  sounder  scientific  basis  than  the  contents  of  total  digestible  nutrients, 
it  is  always  well  to  check  up  such  laboratory  results  by  observations 
obtained  from  feeding  experiments  of  longer  duration.  It  was  the 
purpose  of  the  experiments  to  be  reported  below  to  make  such  de- 
terminations and  observations. 


FIRST  EXPERIMENT:    ALFALFA,  CLOVER,  AND 
TIMOTHY  HAY 

Outline  of  Experiment 

Fifteen  western  ewes,  three  to  four  years  of  age  and  weighing 
approximately  100  pounds  each,  were  divided  into  three  equal  lots, 
the  first  to  receive  alfalfa  hay,  the  second  clover  hay,  and  the  third 
timothy  hay.  Since  it  was  questionable  whether  timothy  hay,  in  the 
amounts  required  for  maintenance  of  body  weight,  would  contain 
enough  protein  to  cover  the  protein  requirement,  each  sheep  in  the 
three  lots  was  given  approximately  .15  pound  of  linseed  oil  meal  per 
100  pounds  initial  live  weight  daily.  A  possible  deficiency  of  timothy 
hay  in  minerals  was  removed  by  allowing  the  timothy-hay  sheep  ac- 
cess to  a  mineral  mixture  consisting  of  equal  parts  of  special  steamed 
bone  meal,  finely  ground  limestone,  and  salt.  In  each  lot  the  con- 
sumption of  hay  was  regulated  so  as  just  to  maintain  the  body  weight 
of  the  sheep.  Under  these  conditions  the  relative  amounts  of  the  dif- 
ferent hays  required  for  maintenance  per  100  pounds  live  weight  repre- 
sent their  relative  values  as  sources  of  nutritive  energy.  All  sheep 
were  individually  fed  and  at  all  times  had  access  to  salt.  Except 
during  feeding,  each  lot  of  sheep  was  allowed  the  run  of  a  pen  ap- 
proximately 1  by  5  rods  in  dimensions. 

Samples  of  feed  were  taken  daily  at  the  barns  at  the  same  time 
that  the  daily  rations  were  weighed  out,  and  these  daily  samples 
were  composited  for  the  entire  experiment  and  submitted  to  routine 
chemical  analysis.  The  analyses  of  these  feed  samples  will  be  found 
in  Table  5. 

At  the  end  of  its  maintenance  period  digestion  and  metabo- 
lism studies  were  made  on  each  of  the  sheep  in  the  three  lots  for  the 
purpose  of  determining  the  content  of  the  maintenance  rations  in  di- 
gestible nutrients  and  in  metabolizable  energy.  The  feed,  feces,  and 


132 


BULLETIN  No.  317 


[December, 


TABLE  5. — PERCENTAGE  COMPOSITION  OF  FEEDS  FED  AT  BARN 


Feed  sample 

Dry  sub- 
stance 

Crude 
protein 

(Nx 
6.25) 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Ash 

Gross 
energy 
per  gram 

Clover  hay  

perct. 
94.73 

perct. 
10.19 

perct. 
43.32 

perct. 
31.70 

perct. 
2.32 

perct. 
7.20 

sm.  cals. 
4  154 

Alfalfa  hay  

93.56 

16.38 

43.52 

22.85 

2.82 

7.99 

4  195 

Timothy  hav  

96.  15 

7.44 

51.19 

27.73 

4.09 

5.70 

4  317 

Linseed  oil  meal  

92.80 

36.19 

36.51 

7.65 

6.53 

5.92 

4  402 

urine  were  submitted  to  a  direct  determination  of  gross  energy  by 
means  of  the  bomb  calorimeter.  These  determinations  afforded  the 
opportunity  of  computing  the  amounts  of  digestible  nutrients  and  of 
metabolizable  energy  required  for  maintenance  for  each  experimental 
ration. 

The  Experimental  Data 

Body  Weights.  The  experimental  feeding  started  July  9,  1924, 
and  within  the  following  two  weeks  the  body  weights  of  the  alfalfa 
and  clover-hay  sheep  were  adjusted  to  the  amounts  of  hay  calculated 
to  be  sufficient  for  maintenance.  The  timothy-hay  sheep  were  much 
slower  in  reaching  a  constant  level. 

In  this  experiment  it  was  considered,  somewhat  arbitrarily,  that 
a  good  determination  of  the  maintenance  requirement  would  result  in 
a  period  of  8  weeks  during  which  the  body  weight  remained  approxi- 
mately constant  on  constant  feed.  Most  of  the  maintenance  experi- 
ments on  the  alfalfa  and  clover-hay  groups  were,  however,  of  13  to 
15  weeks'  duration. 

The  weekly  weights  of  individual  sheep  are  given  in  Table  6. 
One  sheep  in  the  alfalfa-hay  group  died  in  the  early  part  of  September 
from  unknown  causes  and  the  data  on  this  animal  may  not  be  of  any 
considerable  significance.  It  will  be  seen,  however,  that  all  of  the 
alfalfa  and  clover-hay  sheep  maintained  their  weight  at  an  approxi- 
mately constant  level  from  July  23  to  the  time  when  experimental 
feeding  stopped.  While  the  variation  in  weight  from  week  to  week 
was  at  times  considerable,  there  is  no  apparent  tendency  for  the 
weights  of  these  sheep  either  to  increase  or  to  decrease  progressively. 

The  maintenance  trials  on  the  timothy-hay  sheep  were  not  so 
satisfactory,  since  a  constant  level  in  weight  cannot  be  considered  to 
have  been  established  until  September  10.  The  experiment  with  these 
sheep  may  also  be  questioned  on  two  other  grounds.  First,  at  the  end 
of  the  experiment  the  condition  of  the  sheep  was'  noticeably  poorer 
than  that  of  the  sheep  in  the  alfalfa-  and  clover-hay  groups,  indicating 
that  in  part  of  the  feeding  period  at  least  they  had  been  compelled  to 
draw  upon  their  body  stores  of  fat  to  provide  sufficient  energy  for 
maintenance.  This  withdrawal  of  body  stores  very  probably  occurred 
in  the  interval  from  the  beginning  of  the  experiment  to  September  10, 


1988} 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


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BULLETIN  No.  317 


[December, 


during  which  all  decreased  slightly  in  weight.  Second,  thru  a  mis- 
understanding at  the  barns  small  amounts  of  feed  refused  from  the 
amounts  offered  after  October  1  were  not  weighed  or  saved  for  an- 
alysis. This  refused  feed,  however,  is  known  to  be  inconsiderable  in 
amount  and  probably  is  of  no  great  significance  in  interpreting  the 
results  of  the  experiment.  The  effect  of  this  oversight  would  be  to  in- 
troduce an  error  in  the  opposite  direction  from  that  consequent  upon 
a  possible  withdrawal  of  fat  from  the  bodies  of  the  sheep  during  the 
maintenance  trial. 

Digestibility  and  Energy  Content  of  Rations.  The  digestion  and 
metabolism  periods  were  of  10  days'  duration.  Tests  were  run  upon 
each  of  the  15  sheep  in  the  experiment;  the  results  obtained  with  4 
of  the  sheep  had  to  be  discarded,  because  in  these  cases  the  allowance 
of  linseed  oil  meal  was  inadvertently  increased  above  the  allowance 
that  they  had  been  receiving.  Before  the  mistake  was  discovered  these 
sheep  had  been  taken  off  experiment  and  otherwise  disposed  of,  so 
a  repetition  of  their  trials  was  impossible.  However,  three  good  di- 
gestion and  metabolism  studies  remain  on  the  alfalfa  ration,  four  on 
the  clover-hay  ration,  and  four  on  the  timothy-hay  ration.  No  orts 
were  left  in  any  of  these  trials  and  they  were  in  every  respect  satis- 
factory. A  summary  of  the  coefficients  of  digestibility  is  contained  in 
Table'?. 

TABLE  7. — COEFFICIENTS  OF  DIGESTIBILITY  OF  RATIONS 


Sheep  No. 

Dry  substance 

Crude  protein 

X-free  extract 

Crude  fiber 

Ether  extract 

Alfalfa-hay  ration 


156  

perct. 
67 
66 
04  ^ 
65.7 

perct. 
77 
75 
74 
75.3 

fierct. 
79 
78 
7s 
78.3 

perct. 
44 
46 
41 
43.7 

perct. 
63 
54 
59 

5S.7 

157 

158   

Average  

Clover-hay  ration 

160         

61 
56 
60 
56 

58.3 

60 

58 
63 

50 

57.8 

76 

7S 
74 
77 
76.3 

44 
23 
41 
30 
34.5 

80 

76 
81 
80 
79.3 

161  

162 

163 

Average  

Timothy-hay  ration 

165... 

61 
60 
58 
63 
60.5 

61 
61 
61 
57 
60.0 

69 

71 

(IS 
75 
70.8 

53 
42 
46 
47 
47.0 

68 
58 
54 
60 
60.0 

166  

167 

168 

Average  

The  individual  coefficients  for  the  different  rations  agreed  fairly 
well  among  themselves  with  few  exceptions.  For  Table  8  the  digesti- 
bility of  the  hays  alone  has  been  computed,  assuming  an  average  di- 
gestibility for  the  linseed  oil  meal  as  given  in  Henry  and  Morrison's 
"Feeds  and  Feeding."  Because  of  the  small  proportion  of  linseed  oil 


1928}  ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOR  SHEEP 

TABLE  8. — COMPUTED  COEFFICIENTS  OF  DIGESTIBILITY  FOR  HAYS  ALONE 


135 


Sheep  No. 

Dry  substance 

Crude  protein 

N-frer  extract 

Crude  fiber 

r  extract 

Alfalfa-hay  ration 

156  .. 

perct. 
66 
65 
62 
64.3 

perct. 
75 
73 
71 
73.0 

perct. 
79 
78 
77 
78.0 

44 
45 
40 

43.0 

perct. 

.-,7 

18 

••••• 
51.7 

157 

158 

Average  

Clover-hay  ration 

160... 

59 
53 
58 

55 
56.3 

52 
50 
57 

41 
50.0 

75 
7.s 
72 

77 

75.5 

44 
21 
40 
29 
33.5 

78 

71 
7S 
81 

7'i  -  5 

161  

162  

163  

Average  

Timothy-hay  ration 

165... 

59 
57 
55 
61 
58.0 

45 
43 
43 
38 

42.3 

68 
71 
67 
7:. 
70.3 

53 
42 
45 
47 
46.8 

67 

52 
48 

57 
56.0 

166 

167     .      . 

168  

Average  

meal  in  the  rations,  the  coefficients  in  Table  8  are  quite  similar  to 
those  in  Table  7  with  the  exception  of  the  coefficients  of  digestibility 
of  protein  for  timothy  hay,  these  coefficients  being  markedly  lower 
than  the  similar  coefficients  for  the  combined  ration  of  timothy  hay 
and  linseed  oil  meal. 

From  the  average  coefficients  of  digestibility  for  the  three  differ- 
ent rations  and  their  average  chemical  composition,  the  average  con- 
tent of  the  experimental  rations  in  total  and  digestible  nutrients  was 
computed,  the  results  being  given  in  Table  9.  The  alfalfa-hay  and 
timothy-hay  rations  were  very  similar  in  their  content  of  total  digest- 
ible nutrients,  the  clover-hay  ration  being  somewhat  lower  in  this  re- 
spect. The  content  of  total  and  digestible  protein  decreased  from  the 
alfalfa  hay  thru  the  clover-hay  to  the  timothy-hay  ration. 


TABLE  9. — AVERAGE  PERCENTAGE  COMPOSITION  OF  THE 
THREE  EXPERIMENTAL  RATIONS 


Dry  sub- 
stance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Fat 

Ash 

Total  di- 
gestible 
nutrients 

Alfalfa-hay,  oil-meal  ration 

Total  

93.50 

61.43 

18.01 

13.56 

42.94 
33.62 

21.60 
9.44 

3.13 
1.84 

7.82 

66!76 

Digestible  

Clover-hay,  oil-meal  ration 

Total 

94  56 

12.52 

7.24 

42.71 
32.59 

29  .  54 
10.19 

2.70 
2.14 

7.08 

•    I  - 

Digestible  

55.13 

Timothy-hay,  oil-meal  ration 

Total  

94.47 
57.  15 

10.21 
6.12 

49.01 
34.70 

25.34 
11.91 

5.70 
3.42 

5.65 

66!42 

Digestible  

136 


BULLETIN  No.  317 


[December, 


In  the  digestion  trials  the  urine  was  collected  and  analyzed  for 
nitrogen,  permitting  a  determination  of  the  nitrogen  balances.  From 
Table  10  it  is  evident  that  all  the  sheep  were  in  positive  nitrogen  bal- 
ance. In  general  the  positive  balance  with  the  timothy-hay  sheep  was 
less  than  the  balances  for  the  sheep  on  the  other  rations.  However,  the 

TABLE  10. — NITROGEN  BALANCES  OF  SHEEP  IN  MAINTENANCE  PERIODS 


Sheep  No. 

Nitrogen  of 
feed  consumed 

Nitrogen  of 
feces 

Nitrogen  of 
urine 

Total  nitrogen 
excreted 

Nitrogen 
balance 

Alfalfa,  oil-meal  ration 

156 

grams 
26.7 
26.7 
29.6 

grams 
6.1 
6.6 
7.7 

grams 
18.5 
18.0 
20.8 

grams 
24.6 
24.6 
28.5 

gramt 
+2.1 

+2.1 
+2.1 

157  

158  

Clover,  oil-meal  ration 

160.  .. 

21.3 

20.8 
17.0 
20.0 

8.5 
8.6 
6.2 
9.9 

10.7 
10.0 

8.2 
10.0 

19.2 
18.6 
14.4 
19.9 

+2.1 

+2.2 
+2.6 
+   .1 

161  

162 

163  

Timothy,  oil-meal  ration 

165  ... 

11.0 
12.0 
11.5 
10.7 

4.3 
4.6 
4.5 
4.6 

4.9 
4.0 

5.4 
4.8 

9.2 
8.6 
9.9 
9.4 

+  1.8 
+3.4 
+  1.6 
+  1.3 

166  

167  

168  

storage  of  nitrogen  on  the  clover-hay  ration  was  evidently  as  extensive 
as  the  storage  of  nitrogen  on  the  alfalfa-hay  ration  containing  almost 
twice  as  much  digestible  crude  protein. 

The  computations  of  the  metabolizable  energy  of  the  different 
rations  will  be  found  in  Table  11.  The  gross  energy  content  of  feed, 
feces,  and  urine  was  determined  directly  by  the  bomb  calorimeter. 
From  the  daily  intake  of  digestible  carbohydrates  the  methane  pro- 
duction was  estimated  by  means  of  Armsby's  average  factor  and  the 
energy  content  of  the  methane  produced  was  then  computed,  taking 
1  gram  of  methane  equal  to  13.34  calories;  a  small  correction  of  the 
energy  of  the  urine  was  made  to  allow  for  the  storage  of  protein.1  The 
total  metabolizable  energy  of  the  combined  rations  was  computed  per 
kilogram  of  dry  matter  and  per  pound  of  digestible  organic  matter. 
The  average  metabolizable  energy  per  kilogram  of  dry  matter  was 
2.292  therms  for  the  alfalfa-hay  ration,  1.944  therms  for  the  clover- 
hay  ration  and  2.177  therms  for  the  timothy-hay  ration;  per  pound 
of  digestible  organic  matter  the  values  were  respectively,  1.729,  1.589, 
and  1.668  therms.  On  the  basis  either  of  total  dry  matter  or  digestible 
organic  matter  the  alfalfa  ration  was  found  to  contain  the  greatest 
amount  of  metabolizable  energy,  the  timothy-hay  ration  ranking  next 
and  the  clover-hay  ration  least.  The  average  percentage  of  the  gross 

'Armsby,  H.  P.,  and  Fries,  J.  A.  U.  S.  Dept.  Agr.  Bur.  Anim.  Indus.  Bui. 
101,  31.  1908. 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


137 


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1928}  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP  139 

energy  that  proved  to  be  metabolizable  was  51.5  for  the  alfalfa-hay 
ration,  43.9  for  the  clover-hay  ration,  and  48.0  for  the  timothy-hay 
ration. 

Feed  and  Metabolizable  Energy  Requirements  for  Maintenance. 

The  final  computations  of  the  experiment  arc  given  in  Table  12.  The 
maintenance  weight  of  the  individual  sheep  in  the  alfalfa-hay  and 
clover-hay  groups  is  simply  the  average  of  all  weekly  weights  in  Table 
6,  except  for  Sheep  155.  In  this  case  the  last  weight,  taken  two  days 
before  the  death  of  the  animal,  is  not  included  in  the  average.  For  the 
timothy-hay  sheep  the  maintenance  weight  is  taken  as  the  average 
of  the  last  eight  weights  in  Table  6.  During  this  period  the  weights  of 
the  sheep  were  maintained  at  a  practically  constant  level.  The  aver- 
age daily  feed  records  given  in  Table  12  refer  to  the  periods  covered 
by  the  average  maintenance  weights.  The  metabolizable  energy  con- 
sumed daily  was  obtained  by  the  use  of  the  individual  results  of  the 
metabolism  trials  in  the  case  of  those  sheep  upon  which  satisfactory 
trials  were  obtained;  in  the  case  of  Sheep  154,  155,  159,  and  164  the 
average  results  for  their  respective  groups  were  used  in  computing 
their  average  daily  intake  of  metabolizable  energy.  In  the  last  four 
columns  of  Table  12  the  average  daily  intake  of  feed  (in  pounds) 
and  of  metabolizable  energy  (in  calories)  has  been  computed  to  100 
pounds  body  weight,  using  both  the  direct-weight  ratio  and  the  sur- 
face ratio,  i.e.,  the  ratio  of  the  weights  to  the  two-thirds  power.  A 
comparison  of  the  results  obtained  by  the  weight  ratio  with  those  ob- 
tained by  the  surface  ratio  shows  that  the  latter  method  of  compu- 
tation gives  individual  results  within  the  three  groups  agreeing  much 
better  among  themselves.  They  will  therefore  form  the  basis  of  the 
following  discussion. 

The  average  weight  of  feed  required  per  day  per  100  pounds  body 
weight  was  1.917  pounds  for  the  alfalfa-hay  group,  1.824  pounds  for 
the  clover-hay  group,  and  1.593  pounds  for  the  timothy-hay  group.  In 
view  of  the  individual  variations  within  the  different  groups  of  sheep 
the  average  difference  between  the  alfalfa-hay  ration  and  the  clover- 
hay  ration  cannot  be  considered  highly  significant.  The  average  dif- 
ference between  the  timothy-hay  group  and  either  of  the  other  two 
groups  would  seem  to  be  highly  significant,  since  none  of  the  indi- 
vidual results  on  the  alfalfa-hay  ration  or  the  clover-hay  ration  was 
as  low  as  the  highest  result  with  the  timothy-hay  ration.  It  seems 
fair  to  conclude,  therefore,  from  these  results  that  the  timothy-hay 
ration  was  distinctly  higher  in  net  energy  than  either  of  the  other 
rations.  The  results  also  suggest  that  the  clover-hay  ration  was 
higher  in  net  energy  than  the  alfalfa-hay  ration.  Since  the  proportion 
of  linseed  oil  meal  in  the  three  experimental  rations  was  approximate- 
ly the  same,  it  also  seems  fair  to  conclude  that  the  timothy  hay  used 
in  this  experiment  had  a  higher  net  energy  value  than  either  the  alfal- 


140  BULLETIN  No.  317  [December, 

fa  hay  or  the  clover  hay,  and  that  the  clover  hay  probably  was  higher 
in  net  energy  than  the  alfalfa  hay. 

Considering  the  metabolizable  energy  required  per  100  pounds  live 
weight  in  the  three  groups,  the  average  value  for  the  alfalfa  hay  ration 
(1,864  calories)  was  distinctly  higher  than  that  for  either  the  clover- 
hay  ration  (1,521  calories)  or  the  timothy-hay  ration  (1,507  calories). 
Comparing  the  individual  values  of  the  alfalfa-hay  group  with  the 
individual  values  of  the  clover-hay  group,  only  one  result  in  the  former 
group  is  lower  than  the  highest  result  in  the  latter  group.  All  of  the 
individual  results  of  the  alfalfa-hay  sheep  were  higher  than  the  indi- 
vidual results  of  the  timothy-hay  sheep.  On  the  other  hand,  the  av- 
erage metabolizable  energy  required  per  day  per  100  pounds  live 
weight  by  the  clover-hay  sheep  was  practically  the  same  as  that  re- 
quired by  the  timothy-hay  sheep,  the  individual  variations  within 
these  two  groups  rendering  the  small  average  difference  entirely  insig- 
nificant. It  appears,  therefore,  that  for  maintenance  the  metabolizable 
energy  of  clover  liny  is  approximately  of  equal  value  with  that  of 
timothy  hay.  If  it  may  be  assumed  that  the  net  energy  required  for 
maintenance  per  100  pounds  live  weight  was  the  same  in  all  groups, 
it  may  be  concluded  that  the  percentage  availability  of  metabolizable 
energy  was  approximately  the  same  for  clover  hay  as  for  timothy  hay, 
but  was  distinctly  lower  for  alfalfa  hay. 

Summary  of  the  First  Experiment 

The  purpose  of  the  experiment  reported  above  was  to  determine 
the  relative  energy  value  of  alfalfa  hay,  clover  hay,  and  timothy  hay 
for  the  maintenance  of  sheep.  Three  groups  of  mature  sheep  (ewes) 
containing  five  animals  in  each  were  fed  individually  approximately 
.15  pound  linseed  oil  meal  daily  per  100  pounds  initial  live  weight  and 
enough  of  the  three  hays  under  investigation  to  maintain  body  weight. 
A  determination  of  the  digestibility  and  the  content  of  metabolizable 
energy  of  the  three  rations  was  made  on  three  of  the  alfalfa-hay  sheep 
and  four  each  of  the  clover  and  timothy-hay  sheep. 

The  alfalfa-hay  ration  and  the  timothy-hay  ration  contained  ap- 
proximately the  same  percentage  content  of  total  digestible  nutrients, 
i.e.,  60.76  and  60.42  respectively,  while  the  clover-hay  ration  was 
slightly  lower  with  a  percentage  of  54.84.  Since  the  proportion  of  lin- 
seed oil  meal  was  approximately  the  same  in  all  three  rations,  the  con- 
tents of  total  digestible  nutrients  in  the  three  hays  were  probably  in 
the  same  proportion  as  in  the  rations. 

The  average  metabolizable  energy  per  kilogram  of  dry  matter  was 
2.292  therms  for  the  alfalfa-hay  ration,  1.944  therms  for  the  clover- 
hay  ration,  and  2.177  therms  for  the  timothy-hay  ration.  The  alfalfa 
hay  used  in  this  experiment  was  apparently  higher  in  metabolizable 
energy  than  the  timothy  hay,  which  in  turn  was  apparently  higher 
than  clover  hay. 


19-28}  ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOR  SHEEP  141 

The  average  amounts  of  feed  required  per  day  per  100  pounds 
live  weight  were  1.917  pounds  for  the  alfalfa-hay  ration.  1.824  pounds 
for  the  clover-hay  ration,  and  1.593  pounds  for  the  timothy  ration.  A 
comparison  of  the  individual  results  in  the  three  groups  indicates  that 
distinctly  smaller  amounts  of  the  timothy-hay  ration  were  require'! 
maintenance  than  of  the  alfalfa  or  clover-hay  ration.  The  average 
difference  between  the  alfalfa-hay  and  the  clover-hay  ration-  suggi  - 
a  superiority  of  the  latter,  but  in  view  of  the  individual  variations 
within  the  two  groups,  no  positive  conclusion  is  justified. 

The  average  amounts  of  metabolizable  energy  per  day  per  100 
pounds  live  weight  required  for  maintenance  were  1.86-4  caloric- 
the  alfalfa-hay  ration,  1.521  calories  for  the  clover-hay  ration  and 
1,507  calories  for  the  timothy-hay  ration.  A  study  of  the  individual 
data  indicates  that  there  is  no  significant  difference  between  the  clover 
and  timothy  groups  in  this  respect.  However,  distinctly  more  metab- 
olizable energy  was  required  in  the  alfalfa  ration  than  in  either  of 
the  other  two. 

In  view  of  the  similar  proportions  of  linseed  oil  meal  used  in  the 
three  experimental  rations  it  may  be  concluded  that  timothy  hay 
has  a  distinctly  higher  net  energy  value  than  either  alfalfa  hay  or 
clover  hay.  The  results  also  -uggest  that  clover  hay  has  a  slightly 
higher  net  energy  value  than  alfalfa  hay. 

It  may  also  be  concluded  on  the  assumption  that  the  basal  metab- 
olism per  unit  of  body  surface  was  the  same  in  all  groups  that  the 
net  availability  of  the  metabolizable  energy  of  the  alfalfa  hay  was  dis- 
tinctly lower  than  that  of  the  clover  hay  or  of  the  timothy  hay.  Xo 
difference  between  the  latter  two  hays  in  this  respect  was  noted. 

Critical  Consideration 

In  the  preceding  experiment  no  attempt  was  made  with  the  sheep 
getting  the  alfalfa  or  clover  rations  to  maintain  them  at  exactly  their 
initial  weights,  and  as  a  result  certain  adjustments  in  weight  occurred 
to  the  amounts  of  feed  fed.  With  the  sheep  on  the  timothy-hay  ration, 
an  initial  loss  in  weight  was  general  and  in  most  cases  considerable, 
but  these  losses  occurred  in  spite  of  all  that  could  be  done  to  avert 
them.  They  were  due  simply  to  the  refusal  of  the  sheep  to  consume 
enough  of  the  ration  offered.  While  there  is  no  good  reason  to  sup- 
pose that  the  slight  adjustments  of  body  weight  to  feed  that  occurred 
in  the  alfalfa  and  clover  lots  exerted  any  influence  upon  the  energy 
requirements  of  the  sheep,  the  objection  may  be  raised  against  the 
timothy  results  that  the  considerable  losses  in  weight  incurred  by  the 
sheep  in  the  first  few  weeks  of  feeding  may  have  depressed  their  basal 
metabolism  and  possibly  their  activity,  so  that  their  energy  require- 
ments per  unit  of  weight  or  of  surface  were  appreciably  less  than  those 
of  the  alfalfa-hay  and  clover-hay  sheep.  In  such  a  case  the  smaller 


142  BULLETIN  No.  317  [December, 

quantities  of  metabolizable  energy  in  timothy  hay  required  for  main- 
tenance of  weight  would  not  necessarily  indicate  a  greater  percentage 
availability,  but  may  have  been  the  result  entirely  of  a  lowered  re- 
quirement of  net  energy  by  these  sheep. 

That  marked  undernutrition  may  lower  the  basal  metabolism  has 
been  shown  conclusively  by  Benedict,  Miles,  Roth,  and  Smith1  for  men 
and  less  certainly  by  Benedict  and  Ritzman2  for  steers;  a  general  re- 
view of  the  subject  has  been  written  by  Lusk.3  It  appears  that  under 
the  conditions  of  a  greatly  restricted  supply  of  food,  the  body  ad- 
justs itself  to  a  more  economical  level  of  expenditure  as  a  measure  of 
self-preservation.  Such  experiments  do  not  prove  that  small  restric- 
tions of  diet,  occasioning  small  losses  in  body  weight,  will  exert  such 
an  effect  upon  metabolism.  They  also  throw  no  light  upon  the  relation 
of  the  fat  stores  in  the  body  to  the  response  to  a  restricted  diet,  al- 
tho  it  appears  reasonable  to  suppose  that  a  fat  animal  would  respond 
less  quickly  than  a  lean  animal  since  its  stored  food  could,  for  a  time, 
supplement  its  short  rations. 

It  seems  dangerous,  therefore  to  generalize  too  widely  from  the 
limited  data  available,  and  in  particular  to  assume  that  basal  metab- 
olism is  readily  altered  by  the  plane  of  nutrition.  If  this  were  true, 
basal  metabolism  determinations  would  not  show  the  remarkable  con- 
stancy that  has  been  repeatedly  noted  in  human  experimentation  when 
allowance  is  made  for  differences  in  size,  sex,  and  age,  and  standards  of 
basal  metabolism  would  be  of  little  significance,  contrary  to  general 
experience.  Gulick4  has  found  in  his  own  case  that  overmitrition,  in- 
ducing a  20-percent  increase  in  body  weight,  had  no  effect  on  his  basal 
metabolic  rate.  Overmitrition  leading  to  extreme  obesity  (as  much 
as  160  percent  overweight)  has  been  very  conclusively  shown  by 
Means5  to  be  associated  with  normal  basal  metabolic  rates  per  square 
meter  of  body  surface,  a  finding  that  has  been  confirmed  by  Strouse, 
Wang,  and  Dye6  and  others.  The  latter  investigators  have  been  un- 
able to  show  that  underweight  is  consistently  associated  with  lowered 


'Benedict,  F.  G.,  Miles,  W.  R.,  Roth,  P.,  and  Smith,  H.  M.  Human  vitality 
and  efficiency  under  prolonged  restricted  diet.  Carnegie  Inst.  Wash.  Pub.  280. 
1919. 

2Benedict,  F.  G.,  and  Ritzman,  E.  G.  Undernutrition  in  steers:  its  relation 
to  metabolism,  digestion,  and  subsequent  realimentation.  Carnegie  Inst.  Wash. 
Pub.  324.  1923. 

sLusk,  G.  The  physiological  effect  of  undernutrition.  Physiol.  Rev.  1,  523. 
1921. 

"Gulick,  A.  Weight  regulation  in  the  adult  human  body  during  overnutri- 
tion.  Amer.  Jour.  Physiol.  60,  371.  1922. 

•"'Means,  J.  H.  The  basal  metabolism  in  obesity.  Arch.  Int.  Med.  17,  704. 
1916. 

eStrouse,  S.,  Wang,  C.  C.,  and  Dye,  M.  Studies  on  the  metabolism  of 
obesity.  II.  Basal  metabolism.  Arch.  Int.  Med.  34,  275.  1924. 


1928]  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP  143 

basal  metabolic  rates,  and  Blunt  and  Bauer1  have  found  that  among 
a  group  of  nineteen  college  women  who  were  underweight  by  compari- 
son with  life  insurance  standards  and  were  eating  hardly  enough  food 
to  supply  their  estimated  daily  needs,  the  basal  metabolic  rate  aver- 
aged almost  normal.  Also  Morgulis,  in  his  book  on  "Fasting  and 
Undernutrition,"2  cites  an  experiment  performed  in  Benedict's  labora- 
tory on  a  dog,  in  which  a  restriction  in  diet,  causing  a  sharp  drop  in 
body  weight,  was  not  associated  with  a  drop  in  basal  metabolism  per 
kilogram  body  weight. 

It  seems  fair  to  conclude  that  while  underntitrition  may  ultimate- 
ly lower  the  basal  heat  production  of  an  animal,  there  are  conditions 
that  may  defer  or  obscure  this  result  for  considerable  periods  of  time. 
Until  more  is  known  of  these  conditions,  the  result  of  undernutrition 
in  any  particular  case  cannot  be  foretold  with  any  degree  of  certainty. 
In  the  foregoing  experiment  on  sheep  described  in  this  bulletin,  the 
timothy-hay  sheep  were  undernourished  during  the  first  few  weeks  of 
the  experiment.  If  this  undernutrition  had  lowered  their  energy  re- 
quirements,3 it  would  be  expected  that  the  amounts  of  metabolizable 
energy  ultimately  shown  to  be  required  for  maintenance  of  weight 
would  be  inversely  correlated  with  the  losses  in  weight  sustained.  That 
this  is  not  the  case  is  shown  by  the  following  comparison: 

Metabolizable 
energy  required 

Sheep  No.  Average  Average  Loss  in        per  100  pounds 

initial  weight    final  weight        weight  average  live 

weight 
Ibs.  Ibx.  Ibs.  cals. 

164 105  87  18  1  168 

166 116  99  17  1  534 

167 Ill  98  13  1  600 

168 101  94  7  1  633 

165. .  99  94  5  1  598 


'Blunt.  K..  and  Bauer.  V.  The  basal  metabolism  and  food  consumption  of 
underweight  college  women.  Jour.  Home  Econ.  14,  171,  226.  1922. 

2Morgulis.  S.  Fasting  and  undernutrition:  a  biological  and  sociological 
study  of  inanition,  226.  E.  P.  Button  &  Co.  1923. 

3It  is  of  course  recognized  that  these  requirements  relate  to  voluntary  mus- 
cular activity  as  well  as  to  basal  metabolism.  The  above  discussion  has  been 
necessarily  confined  to  the  effect  of  undernutrition  on  the  basal  metabolic  rate 
since  no  quantitative  information  has  been  found  concerning  its  relation  to 
voluntary  activity.  However,  the  experiments  reported  by  Trowbridse.  Moulton, 
and  Haigh  (Mo.  Res.  Bui.  18),  on  the  live-weight  maintenance  requirements  of 
cattle,  may  be  cited  in  this  connection.  In  these  long-continued  maintenance 
trials  no  effect  of  the  condition  of  the  steers  can  be  detected  when  all  of  the  data 
are  considered;  in  particular  a  restricted  food  intake  induced  a  somewhat  higher 
maintenance  cost  per  unit  of  area  in  the  average  (Tables  23  and  24,  and  con- 
clusion 9).  The  later  calculations  of  Hogan,  Salmon  and  Fox  (Mo.  Res.  Bui.  51, 
1922)  on  growing  and  fattening  steers,  leading  to  the  conclusion  that  the  main- 


144  BULLETIN  No.  317  [December, 

The  sheep  are  arranged  in  the  order  of  decreasing  losses  in  weight, 
and  it  is  evident  that,  disregarding  the  exceptionally  low  result  for 
Sheep  164, x  there  is  no  progressive  or  considerable  increase  in  energy 
requirements  with  decreasing  losses  in  weight. 

It  is  frankly  admitted,  however,  that  the  results  obtained  with 
the  timothy-hay  sheep  may  not  be  strictly  comparable  with  those 
obtained  in  the  other  lots  for  the  reasons  explained  above,  and  while 
it  seems  very  unlikely  that  the  conclusion  drawn  from  the  comparison 
is  vitiated,  it  was  considered  advisable  to  repeat  the  alfalfa  hay-tim- 
othy hay  comparison  in  a  second  experiment  planned  to  meet  so  far 
as  possible  the  objections  that  may  be  raised  against  the  first. 


SECOND  EXPERIMENT:     ALFALFA  AND  TIMOTHY  HAY 
Outline  of  Experiment 

It  was  realized  at  the  outset  of  this  experiment  that  it  would 
be  difficult  to  induce  sheep  to  consume  enough  of  a  ration  consisting 
largely  of  timothy  hay  to  maintain  weight.  It  was,  therefore,  planned 
to  start  two  groups  of  sheep,  one  to  receive  a  timothy  ration  and  one 
an  alfalfa  ration,  and  to  limit  the  food  consumption  of  the  alfalfa-hay 
sheep,  if  necessary,  so  that  they  would  exhibit  the  same  losses  in 
weight  as  the  timothy-hay  sheep.  At  the  end  of  15  weeks  the  rations 
were  to  be  changed,  each  sheep  receiving  as  much  of  the  second  ration 
as  it  had  been  consuming  of  the  first. 

Nineteen  western  wethers  and  one  ewe,  averaging  93  pounds 
per  head,  were  obtained  in  February,  1926,  for  this  experiment.  Six 
were  slaughtered  on  February  23  and  analyzed  to  determine  the  initial 
composition.  The  remaining  14  were  divided  into  two  lots,  one  to  be 
fed  the  alfalfa  ration  and  one  the  timothy  ration.  The  timothy-hay 
sheep  were  later  reduced  to  six,  since  one  proved  to  be  a  poor  feeder. 

As  in  the  first  experiment,  the  sheep  were  individually  fed  and 
received  in  addition  to  the  roughage  approximately  .08  pound  of  lin- 
seed oil  meal  daily  per  100  pounds  initial  body  weight,  All  sheep  had 
access  to  salt  at  all  times,  and  when  consuming  timothy  hay  they 
also  received  a  small  amount  (6  grams)  of  steamed  bone  meal  daily. 
The  individual  feeding  crates  are  illustrated  in  Fig.  1. 

tenance  energy  cost  increases  with  the  plane  of  nutrition,  are  of  less  certain  sig- 
nificance since  the  energy  storage  in  the  gains  had  to  be  estimated  and,  in  par- 
ticular, since  the  assumption  is  made  that  the  net  energy  value  of  feeds  is  the 
same  at  different  levels  of  feeding.  This  assumption  cannot  be  justified  by  ex- 
perimental findings  and  for  low  and  high  levels  it  is  incorrect  in  all  probability. 
nXo  digestion  and  metabolism  experiment  was  run  on  this  sheep.  The  aver- 
age results  of  the  other  four  sheep  were  used  in  the  calculation  of  the  metaboliz- 
able  energy  content  of  the  maintenance  ration  in  this  case. 


1928} 


ALFALFA.  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


145 


It  was  found  that  the  timothy-hay  sheep  would  not  consume  con- 
tinuously more  than  1  pound  per  head  daily,  and  on  March  1  the 
feeding  experiment  began  with  this  group  at  this  level.  The  alfalfa- 
hay  sheep  were  started  at  1.5  pounds  of  hay  daily  per  head,  but  were 
later  reduced  to  1  pound  also,  since  on  the  higher  level  they  gained 
in  weight.  All  sheep  lost  slowly  in  weight  on  1  pound  of  roughage  daily, 
but  the  losses  in  the  two  groups  were  very  closely  the  same. 

During  May  and  June  all  sheep  were  subjected  to  a  digestion 
and  metabolism  trial  lasting  ten  days,  during  which  there  were  no  feed 
residues.  On  June  2  the  sheep  were  sheared  and  on  June  14  the  ra- 
tions were  reversed. 

After  the  change  in  ration  all  sheep  continued  to  lose  slowly  in 
weight,  and  in  July  the  first  deaths  occurred  among  those  receiving 


FIG.  1. — THE  INDIVIDUAL  FEEDING  CRATES  USED  IN  THE 
EXPERIMENT 


alfalfa  hay.  In  this  group  two  sheep  died  on  July  12  and  13  respec- 
tively, and  one  on  August  19.  On  September  13  the  remaining  three 
sheep  on  the  alfalfa  ration  were  again  put  in  the  metabolism  crates  for 
a  ten-day  period,  immediately  after  which  two  of  them  died  with 
no  apparent  symptoms  but  those  of  malnutrition.  The  remaining  sheep 
was  slaughtered  and  analyzed  on  September  27. 

Among  the  sheep  receiving  timothy  hay  in  the  second  period  of 
the  experiment,  no  deaths  occurred  until  September,  when  three  died 
on  the  16th,  19th,  and  24th,  respectively.  The  remaining  four  sheep 
were  put  into  the  metabolism  crates  for  ten  days  and  were  then 
slaughtered,  one  on  September  27  and  three  on  October  4. 


146 


BULLETIN  No.  317 


[December, 


Results  of  the  Second  Experiment 

Chemical  Composition  of  the  Check  Sheep.  The  live  weights, 
empty  weights,  and  fill  of  the  six  check  sheep,  slaughtered  at  the  be- 
ginning of  the  experiment,  are  given  in  Table  13.  An  average  of  72 
percent  of  the  "fill"  was  contained  in  the  first  three  stomachs.  The 
average  weight  of  wool  shorn  from  the  sheep  before  slaughter  was  5.5 
pounds.  The  average  weight  of  blood  collected  was  4.06  pounds,  and 
the  weights  of  caul  fat  and  gut  fat  averaged  2.03  and  .98  pound  re- 
spectively. The  dressing  percentage  ranged  from  44.4  to  50.3,  aver- 
aging 47.8. 

TABLE  13. — LIVE  WEIGHT,  EMPTY  WEIGHT,  AND  FILL  OF  CHECK  SHEEP 


Sheep  No. 

Live  weight 

Empty  weight 

Fill 

Fill 

34  

Ibs. 
70.1 

lb». 

62.2 

Rw. 

7.9 

perct. 
11.2 

50 

91.2 

79  3 

11  9 

13   1 

11  

116.  1 

100.6 

15.6 

13.4 

30  

83.2 

70.3 

12.9 

15.5 

12      . 

97.2 

87  3 

9  9 

10  2 

44  

88.9 

78.9 

10.0 

11.2 

Average  

91.1 

79.8 

11.4 

12.4 

The  entire  carcass  of  each  sheep  was  divided  for  analysis  into 
three  samples:  (1)  the  flesh  sample  contained  the  boneless  meat  on 
one  half  of  the  dressed  carcass,  including  one  kidney,  the  left  half  of 
the  carcass  not  being  analyzed ;  (2)  the  bone  sample  included  the 
bones  of  one  half  the  dressed  carcass,  separated  by  knife,  and  the 
bones  of  the  head  and  of  two  of  the  feet;  and  (3)  the  offal  sample, 
made  up  of  the  blood,  the  hide,  the  flesh  on  the  head,  the  abdominal 
fat,  and  all  of  the  viscera  with  the  exception  of  the  kidneys.  The  wool 
of  all  six  sheep  was  composited  for  analysis. 

The  weights  of  these  samples  from  each  sheep  and  the  aver- 
ages for  all  will  be  found  in  Table  14,  while  the  results  of  their  chemi- 

TABLE  14. — WEIGHTS  OF  SAMPLES  ANALYZED  (FRESH  BASIS)  CHECK  SHEEP 

(All  weights  in  kilograms) 


34 

50 

11 

30 

12 

44 

Average 

11.20 

15  87 

21.50 

13.09 

18.02 

16.22 

15.98 

3.92 

4.41 

5.03 

4.15 

4.76 

4.37 

4.44 

Offal  samples  

8.52 

12.79 

13.66 

9.83 

12.02 

10.41 

11.21 

cal  analysis  are  given  in  Table  15.  Besides  the  ordinary  routine  de- 
terminations the  calcium  was  determined  in  these  samples  by  the 
method  of  McCrudden1  and  the  gross  energy  by  combustion  in  the 
Pan-  oxygen  bomb  calorimeter. 

From  these  sample  analyses  the  composition  of  the  entire  car- 
casses of  the  sheep  has  been  calculated  on  the  basis  of  the  empty 

McCrudden,  F.  H.    Jour.  Biol.  Chem.  7,  83,  1910;    10,  187,  1911-12. 


1928]  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 

TABLE  15. — PERCENTAGE  COMPOSITION  AND  ENERGY  CONTEXT  OF 
SAMPLES  FROM  THE  CHECK  SHEEP 


147 


Sheep 

No. 

Dry 
substance 

Total 
nitrogen 

Crude 
protein 

Ether 
extract 

Ash 

Calcium 

^•rgy 
•  uram 

Edible-flesh  samples 


34... 

3S  .  24 

3.02 

18.88 

16.61 

.96 

.  022 

.-•m.  cals. 
2  536 

50     ...    . 

4.">  77 

2  .  57 

16  06 

27.  (19 

.  SO 

027 

3  330 

11  

57  .  50 

2  .  28 

14  .  25 

40  .  05 

.69 

.019 

.     .M  • 

30    .  . 

40   84 

2  79 

17  44 

23  OS 

94 

• 

',  i  Q2 

12 

."2  77 

2.58 

16.13 

30  27 

.81 

017 

3 

44  

50.32 

2.47 

15.44 

3  i  .  NS 

.75 

.025 

oil 

Average 

47.99 

2.62 

16.37 

28.66 

.84 

.  023 

3  514 

Bone  samples 


34 

59  66 

3.29 

20  .  59 

is.  31 

18.50 

I 

•>  s54 

50          .     . 

59   71 

3.46 

21.62 

20.04 

17.34 

6  4>; 

•2  836 

11  

61.14 

3.49 

21.  S3 

17  .  58 

20.09 

7.50 

2  828 

30 

5»   95 

3  4S 

21  77 

17  71 

18  32 

6  M 

2   v>3 

12         .    . 

BO.  88 

3.45 

2  1  .  5s 

20  .  37 

17.99 

6  98 

3  042 

44  

65.00 

3.31 

20.68 

21.88 

20.56 

7.73 

3   169 

Average 

60  .  S9 

3.41 

21.35 

19.32 

18.80 

7.07 

2  925 

Offal  samples 


34... 

30.  So 
34  .  34 
40  .  64 
30.12 
37.49 
41.  SO 
35  ^7 

2.70 
2.33 
2.34 
2.50 
2  .  68 
2.21 
2.46 

16.86 

14.58 
14.65 
15.62 
16.75 
13.81 
15.38 

12.57 
17.91 
23  .  95 
12.71 

lv.  Mi 

25.97 
ls.66 

1.05 
.87 
.94 
1.09 
.95 
.73 
.94 

.035 
.034 
.032 
.038 

!627 

.033 

2   119 
2  501 
•_'  960 
2   149 
2  651 
3  2S4 
2  611 

50  

11  

30       ... 

12  

44  

Average 

Wool  sample 

94.74 

9.31               58.19 

21.85 

14.7 

.  250 

5  756 

TABLE  16.  —  PERCENTAGE  COMPOSITION  AND  GROSS  ENERGY  CONTENT 
OF  THE  CHECK  SHEEP 

Sheep 

No. 

Live  or 
empty 

weight 

Dry 
substance 

Crude 
protein 

Ether 
extract 

Ash 

Calcium 

Gross 
energy 
per  gram 

On  basis  of  live  weight 


34... 

A'ffs. 
31.80 

36.51 

IS.  26 

13.19 

4.05 

sjn.  cals. 
2  263 

50  
11  

41.39 
52.68 

40  .  22 
44.32 

16.47 
14.45 

19.37 
25  .  27 

3.33 

3.14 

.72 
.74 

2  ti'.K 
3  147 

30  

37.76 

34.72 

16.34 

14.70 

3.59 

.78 

2  300 

12 

44.11 

43  69 

16  77 

20  94 

3.36 

.77 

2  S74 

44 

40.32 

43  .  93 

15.61 

24  .  46 

3.63 

.87 

3  162 

Average 

41.34 

40.57 

16.32 

19.66 

3.52 

.SO 

2  741 

On  basis  of  empty  weight 


34         .    . 

28.23 

41    12 

20  .  57 

14.  S6 

4.56 

1.00 

2   519 

50  

35.97 

46.28 

IS.  9! 

22.29 

3  .  S3 

! 

3   102 

11  

45.61 

51.19 

16.69 

29.  IS 

3.62 

.86 

- 

30 

31.91 

41.09 

19.34 

17   39 

4.25 

.93 

2  722 

12  

39.62 

4S.64 

1  S  .  67 

23.31 

3.74 

.86 

3  200 

44  

35.80 

49.48 

1  7  .  5S 

27.54 

4.  os 

- 

3  561 

Average 

36.19 

46.30 

18.63 

22.43 

4.01 

.91 

3   128 

weight  and  of  the  live  weight, 
given  in  Table  16. 


The  results  of  these  calculations  are 


148 


BULLETIN  No.  317 


[December, 


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1928} 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


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150 


BULLETIN  No.  317 


[December, 


The  sheep  were  evidently  not  uniform  in  composition.  The  heavier 
individuals  were  in  good  condition  since  they  contained  20  to  25 
percent  of  fat,  but  the  lighter  individuals  were  considerably  less  fat. 

Feeding  Period  and  Changes  in  Body  Weight.  During  the  feed- 
ing of  the  other  two  groups  of  sheep  at  the  barns,  samples  of  the 
feed  were  taken  daily  and  composited  for  analysis  at  approximately 
monthly  intervals  in  so  far  as  possible.  In  addition  to  these  samples 
were  those  taken  during  the  metabolism  periods.  The  percentage  com- 
position of  all  samples  is  summarized  in  Table  17. 

The  individual  feeding  of  the  sheep  started  on  February  22,  but 
the  first  week  was  considered  as  preliminary  in  character.  The  sheep 
of  Lot  1,  consuming  the  timothy-hay  ration,  were  adjusted  to  a  daily 
intake  of  1  pound  of  hay  per  head  and  .08  pound  of  linseed  oil  meal 
per  100  pounds  initial  body  weight  by  March  1,  but  the  sheep  of  Lot 
2  were  given  1.5  pounds  of  hay  until  March  2,  when  the  ration  was 
cut  to  1  pound  of  hay  per  head  and  .08  pound  of  linseed  oil  meal 
per  100  pounds  initial  body  weight  in  view  of  their  rapid  gain  in 

TABLE  18. — WEEKLY  BODY  WEIGHTS  OF  THE  SHEEP  IN  LOT  1 

(All  weights  in  pounds) 


Sheep  No  

2          |          3 

6 

8 

10                  11 

Average 

Period  I — Timothy  hay 


Feb.  22  

78 

85 

103 

83 

96 

98 

90  5 

Mar.  1  

69 

77 

92.5 

67.5 

87 

86 

79.8 

8 

71 

75  5 

91  5 

71 

87 

88 

80  7 

15  .... 

73.5 

77.5 

96 

73 

90 

87 

82  8 

22  

73 

76.5 

93 

70 

85 

83 

80.1 

29 

74 

78 

86 

71 

86 

83 

79  7 

April  5  

70 

74 

85 

70 

86 

82 

77  8 

12  

72 

75 

88 

71 

87 

83 

79.3 

19  . 

71 

73 

86 

68 

85 

79 

77  0 

26  

75 

76 

87 

70 

87 

80 

79  2 

May  3 

68 

74 

90 

69 

86 

78 

77  5 

10 

70 

72 

86 

67 

S3 

74 

75.3 

17  

74 

75 

So 

68 

87 

76 

77.5 

24 

65 

69 

8.3 

72 

86 

75 

75  0 

31  ... 

70 

74 

82 

65 

82 

77 

75  0 

June  7  

63 

58.5 

74 

58.5 

74 

70.5 

66.4 

14 

70 

67.5 

78 

67.5 

79 

70  5 

72  1 

Average  

69.  61 

72.  31 

85.  31 

67.  81 

83.  81 

78.  41 

Period  II— Alfalfa  hay 


June  14  

632 

602 

69" 

612 

712 

62' 

64.  3" 

21 

63 

58 

65 

60 

68 

65 

63  2 

28  .. 

61 

60 

66 

62 

70 

63 

63.7 

July  5  

61 

63 

71 

64 

73 

65 

66.2 

12 

58 

47 

64 

60 

68 

63 

60.0 

19  

60 

Died  7-12 

69 

60 

Died  7-13 

65 

26  

57 

63 

59 

61 

Aug.  2 

57 

63 

59 

61 

9  

57 

64 

57 

62 

16 

58 

66 

54 

62 

23  

56 

62 

Died  8-19 

61 

30 

55 

61 

58 

Sept.  6 

53 

65 

58 

13  

52 

60 

56 

14 

52 

58 

57 

23  

51 

58 

55 

Average  

57.3 

57.6 

64.2 

59.3 

70.0 

61.0 

"The  sheep  were  sheared  on  June  2,  but  the  weights  given  on  June  7  and  14  include  the  wool 
weights.  In  the  averages,  however,  the  sheared  weights  on  these  dates  have  been  used.  'Sheared 
weights. 


1928} 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


151 


weight.  The  experimental  period  with  this  lot  was  not  considered 
as  starting  until  March  22.  The  weekly  weights  of  the  sheep  thruout 
the  two  periods  of  feeding  will  be  found  in  Tables  18  and  19. 

TABLE  19. — WEEKLY  BODY  WEIGHTS  OF  THE  SHEEP  IN  LOT  2 

(All  weights  in  pounds) 


Sheep  No  

1 

4 

5 

7        I         9 

33 

60 

Average 

Period  I—  Alfalfa  hay 

Feb.  22  

84 

78 
79 
83 
SO 
80 
79 
79 
78 
79 
75 
72 
76 
70 
78 
74.5 
75.5 
75.21 

83 
72.5 
76.5 
78 
74 
74 
72 
73 
70 
73 
70 
69 
72 
67 
74 
62.5 
67.5 
69.01 

87 
82 
81.5 
85 
80 
78 
77 
78 
77 
77 
77 
75 
77 
75 
75 
66.5 
71.5 
74.  41 

99 
90 
90.5 
93 
89 
87 
88 
86 
84 
85 
82 
80 
81 
84 
78 
72.5 
76.5 
81.41 

86 
78 
80.5 
86.5 
82 
82 
80 
81 
78 
80 
76 
75 
74 
74 
72 
67.5 
72.5 
75.51 

82 
71 
76 
75 
74 
74 
73 
76 
73 
75 
75 
68 
71 
70 
74 
68 
68 
70.81 

102 
90 
92 
96 
90.5 
88 
87 
88 
85 
86 
84 
80 
82 
82 
83 
75.3 
75.3 
82.21 

89 
80.1 
82.3 
85.2 
81.4 
80.4 
79.4 
80.1 
77.9 
79.2 
77.0 
74.1 
76.1 
74.6 
76.3 
69.5 
72.4 

Mar      1 

8    

15  

22 

29    

Apr.     5    

12  

19 

26    

May     3   

10 

17            .... 

24  

31  

June     7 

14.                   ..    .. 

Average  

Period  II — Timothy  hay 


66J 

57  2 

63* 

69* 

66» 

59" 

67  « 

63.9 

21  

64 

58 

60 

69 

65 

62 

70 

64.0 

28 

61 

60 

64 

71 

64 

61 

70 

64.4 

July  5  

66 

62 

65 

77 

70 

63 

70 

67.6 

12  

64 

55 

61 

72 

61 

58 

69 

62.9 

19 

65 

61 

66 

65 

67 

60 

69 

64.7 

26   .... 

59 

55 

61 

65 

60 

58 

65 

60.4 

Aug.  2  

60 

54 

61 

63 

60 

58 

65 

60.1 

9  

62 

54 

61 

65 

61 

59 

66 

61.1 

16 

61 

58 

66 

69 

64 

62 

68 

64.0 

23  

63 

56 

63 

67 

64 

62 

67 

63.1 

30  

60 

51 

60 

62 

59 

56 

63 

58.7 

Sept.  6 

59 

53 

62 

63.5 

59 

56 

62 

59.2 

13 

59 

51 

60 

60 

56 

55 

60 

57.3 

20 

60 

51 

60 

Died 

Died 

24  

57 

52 

59 

9-16 

9-24 

53 

Died 

Oct.   3  

58 

50 

59 

9-19 

Average  

61.4 

55.2 

61.8 

66.8 

61.9 

58.9 

66.1 

]These  averages  include  the  period  starting  with  the  weight  of  March  22.  They  also  include  the 
shorn  weights  of  June  7  and  June  14  instead  of  these  weights  plus  the  wool  removed  on  June  2,  as  given 
in  the  table.  'Sheared  weights. 


Amount  and  Composition  of  Wool  Sheared  at  End  of  Period  I. 

On  June  2  all  sheep  were  sheared,  the  individual  weights  of  fleeces 
being  as  follows: 


Lot  1— Timothy 


No. 


2  

Ibs. 
70 

3  

7.5 

6  

9.0 

8  

6.5 

10  

8.0 

11.. 

..8.5 

Average 7 .75 


Lot  2— Alfalfa 


No. 


1 

Ibs. 
9.6 

4   

10.5 

5 

8.5 

7 

7.5 

9 

...   6.5 

33           

8.0 

60.  . 

.  8.3 

Average 8 .40 


152 


BULLETIN  No.  317 


[December, 


The  wool  from  the  alfalfa  sheep  averaged  slightly  heavier  per 
head,  but  the  lot  difference  is  certainly  not  significant.  The  wool 
from  each  lot  of  sheep  was  composited  and  analyzed  as  a  separate 
sample,  with  the  following  results: 


Dry  Total  Crude  Ether 

matter  nitrogen  protein  extract 

Wool  from  timothy 

sheep SS.56  7.79  48.69  22.44 

Wool  from  alfalfa 

sheep 91.00  7.95  49.69  22.02 


Ash 


11.89 
13.73 


Gross 
energy 

(sm.  cals. 

per  gm.) 

4  907 i 

5  068 


('Estimated  from  chemical  composition,  assuming  the  gross  energy  values  of  protein  and  fat  to  be 
5.7  and  9.5  calories  per  gram  respectively.) 

Apparently  there  was  no  significant  difference  in  the  percentage 
composition  as  well  as  in  the  weight  of  the  wool  from  the  two  lots  of 
sheep. 

Digestibility  and  Metabolizable  Energy  Content  of  Rations.  The 
digestion  and  metabolism  trials  inserted  at  the  end  of  the  two  experi- 
mental periods  yielded  information  relative  to  the  digestibility  of  and 
the  content  of  metabolizable  energy  in  the  two  rations.  The  co- 
efficients of  digestibility  obtained  from  these  data  will  be  found  in 
Table  20.  The  timothy-hay  ration  was  evidently  considerably  less  di- 
gestible than  the  alfalfa-hay  ration  with  respect  to  dry  matter,  crude 
protein,  and  nitrogen- free  extract.  On  the  average  the  dry  matter  of 
the  timothy-hay  ration  was  only  82  percent  as  digestible  as  that  of  the 


TABLE  20. — SUMMARY  OF  DIGESTION  COEFFICIENTS 


Sheep 
No. 

Dry 
substance 

Crude 
protein 

N-free 
extract 

Crude 
fiber 

Ether 
extract 

Alfalfa,  oil-meal  ration 


Period  I  

1 

60 

73 

67 

51 

37 

Period  II  

4 
5 
7 
9 
33 
60 

2 

58 
57 
53 
54 
53 
54 

56 

70 
69 
68 
73 
70 
70 

72 

66 
66 
62 
62 
61 
63 

61 

47 
45 
33 
35 
37 
36 

49 

32 
35 
44 
43 
26 
35 

55 

Average  

6 
11 

60 
58 
56.3 

77 
72 
71.4 

64 
65 
63.7 

52 
53 
43.8 

44 
55 
40.6 

Timothy,  oil-meal  ration 


Period  I  

2 

49 

53 

56 

42 

53 

Period  II  

3 
6 

8 
10 
11 

1 

46 
44 
47 
48 
37 

50 

45 
38 
32 
38 
27 

40 

53 
51 
56 
57 
46 

57 

42 
41 
45 
45 
33 

52 

62 
45 

51 
47 
32 

49 

Average  

4 
5 
33 

46 

48 
48 
46.3 

30 
37 
40 
38.0 

55 
57 
57 
54.5 

46 
53 
49 
44.8 

29 
33 
36 
43.7 

1928} 


ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOR  SHEEP 


153 


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154 


BULLETIN  No.  317 


[December, 


alfalfa-hay  ration,  the  crude  protein  only  53  percent  as  digestible, 
and  the  nitrogen-free  extract  only  86  percent  as  digestible. 

The  losses  of  energy  and  the  metabolizable-energy  content  of  the 
rations  were  calculated  in  the  usual  manner,  with  the  results  given 
in  Table  21.  The  alfalfa  ration  contained,  on  an  average,  2.047  therms 
of  metabolizable  energy  per  kilogram  of  dry  matter,  and  3.737  therms 
per  kilogram  of  digestible  nutrients.  For  the  timothy-hay  ration  these 
values  were  1.614  and  3.353  therms  respectively.  For  the  same  weight 
of  dry  matter,  the  timothy-hay  ration  contained  only  79  percent  as 
much  metabolizable  energy  as  the  alfalfa-hay  ration.  An  average  of 
45.47  percent  of  the  gross  energy  of  the  alfalfa-hay  ration  proved  to 
be  metabolizable,  while  only  36.93  percent  of  the  gross  energy  of  the 
timothy-hay  ration  was  metabolizable. 

Nitrogen  Balances.  The  nitrogen  balances  of  the  sheep  during 
the  digestion  periods  are  given  in  Table  22.  A  negative  balance  was 
indicated  in  a  large  majority  of  the  periods;  the  alfalfa  ration,  con- 

TABLE  22. — NITROGEN  BALANCES  OF  THE  SHEEP  DURING  DIGESTION  PERIODS 

(All  weights  in  grams) 


Sheep 
No. 

Nitrogen 
in  feed 

Nitrogen 
in  feces 

Nitrogen 
in  urine 

Nitrogen 
excreted 

Nitrogen 
balance 

Alfalfa,  oil-meal  ration 

Period  I  

1 

4 
5 
7 
9 
33 
60 

2 
6 

11 

12.02 
12.02 
12.35 
12.99 
12.67 
12.82 
13.14 

11.22 
11.55 
11.55 
12.23 

3.30 
3.65 
3  .  84 
4.18 
3.46 
3.81 
3.89 

3.12 

2  .  62 
3.18 
3.51 

8.18 
8.43 
9.01 
10.40 
9.45 
8.38 
9.65 

7.95 
9.05 

8.27 
8.88 

11.48 

12.08 
12.85 
14  .  58 
12.91 
12.19 
13.54 

11.07 
11.67 
11.45 
12.38 

.54 
-    .06 
-    .50 
-1.59 
-    .24 
.63 
-    .40 

.15 
-    .12 
.10 
-    .15 

Period  II  

Average  

Timothy,  oil-meal  ration 

Period  I  

2 
3 
6 
8 
10 
11 

1 
4 
5 
33 

5.71 
5.71 
5.18 
4.86 
5.18 
4.77 

3.92 
3.92 
4.24 
4.00 
4.75 

2.67 
3.14 
3.20 
3.31 
3.20 
3.47 

2.35 
2.74 
2.69 

2^92 

3.78 
4.00 
3.08 
3.36 
4.14 
2.94 

2.45 
3  .  43 
2.95 
2.94 
3.31 

6.45 
7.14 
6.28 
6.67 
7.34 
6.41 

4.80 
6.17 
5.64 
5.32 
6.22 

-    .74 
-1.43 
-1.10 
-1.81 
-2.16 
-1.64 

-    .88 
-2.25 
-1.40 
-1.32 
-1.47 

Period  II  

Average  

taining  over  twice  the  nitrogen  of  the  timothy  ration,  occasioned  small- 
er losses  of  nitrogen. 

Chemical  Composition  of  Surviving  Sheep.  At  the  end  of  the 
experiment  5  sheep  remained  alive  in  a  greatly  emaciated  condition, 
4  from  the  timothy-hay  ration,  and  only  1  from  the  alfalfa-hay  ration. 
They  were  slaughtered  and  analyzed  to  determine  their  fat  and  energy 
content  in  particular,  and  to  permit  of  some  estimate  of  the  loss  of 


19*8] 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


155 


body  energy  sustained  by  the  sheep  during  the  two  periods  of  ex- 
perimental feeding.  The  "fill"  of  these  sheep  averaged  11.43  pounds, 
or  21.5  percent  of  their  live  weight,  and  the  dressing  percentage  aver- 
aged 39.6  and  ranged  from  33.5  to  46.0.  There  were  practically  no  ab- 
dominal fat  deposits,  nor  was  there  enough  visible  fat  on  the  carcass 
to  separate  with  the  knife. 

The  chemical  samples  were  prepared  in  the  same  manner  as  for 
the  check  sheep  in  this  experiment.  Their  weights  are  summarized  in 
Table  23  and  their  percentage  composition  in  Table  24.  The  extreme 
leanness  of  these  sheep  is  shown  particularly  in  the  low  fat  content  of 
the  flesh  and  offal  samples.  For  three  of  the  sheep  (Nos.  11,  33,  and 

TABLE  23. — WEIGHTS  OF  SAMPLES  ANALYZED  FROM  THE  SURVIVING  SHEEP 

(All  weights  in  kilograms) 


Sheep  No  

11 

33 

1 

4 

6  915 

6.906 

7.356 

4.906 

6  220 

6  461 

3.849 

4  .  107 

3.669 

3.538 

4  667 

3  966 

Offal  sample  

6.827 

6.380 

6.617 

5.191 

7  .  530 

6.509 

Wool  sample  

.667 

.740 

.715 

.606 

.  545 

.655 

TABLE  24. — PERCENTAGE  COMPOSITION  AND  ENERGY  CONTENT  OF 
SAMPLES  FROM  THE  SURVIVING  SHEEP 


Sheep  No. 

Dry 
substance 

Total 
nitrogen 

Crude 
protein 

Ether 
extract 

Ash 

Gross 
energy 
per  gm. 

Edible-flesh  samples 


11.  . 

24  94 

3  01 

18  81 

5  12 

1  09 

sm.  cals. 
1  537 

33  

25  30 

2.93 

18  31 

4  09 

1  05 

1  423 

1  

23.93 

3.18 

19.88 

3.08 

1.09 

1  404 

4  

20.59 

3.09 

19.31 

.63 

1  .  OS 

1   138 

5        .... 

19  39 

2  74 

17   13 

1  70 

1  02 

1  097 

Average  

22.83 

2.99 

18.69 

2.92 

1.07 

1  320 

Bone  samples 


11 

60  50 

2  91 

18  21 

20  62 

20  56 

2  917 

33  

54.90 

2.83 

17.70 

19.44 

17.62 

2  736 

1.  ...                 ... 

53.88 

2  S7 

17.92 

15.05 

IS.  til) 

2  5S3 

4  

36.84 

2.94 

IS.  36 

1.27 

17.07 

1   167 

5  

34.02 

2.33 

14.55 

5.98 

13.06 

1  382 

Average1  

Offal  samples 


11.  . 

24  31 

•2  S7 

17  94 

4.86 

1.40 

1  491 

33  

24.11 

2.73 

17.06 

5.75 

1.20 

1  501 

1  

24.04 

2.S2 

17.63 

4.83 

l  .  :.s 

1  465 

4 

21  75 

2  94 

IS  38 

2.61 

1  .  29 

1  203 

',  

20.25 

2  58 

16.13 

3.19 

1  .  3U 

1   214 

Average  

22.89 

2.79 

17.43 

4.25 

1.37 

1   3S7 

Wool  samples 


11 

87  34 

7.19 

44  94 

18.97 

14.04 

4  707 

33 

89.66 

7.96 

49  75 

19.86 

14.64 

5  077 

1,  4,  5     

S7  .  53 

8.00 

50.00 

18.11 

15.43 

4  907 

Average2  

87.92 

7.83 

48.94 

18.63 

14.99 

4  901 

'The  individual  bone  samples  were  too  variable  in  composition,  particularly  in  regard  to  the  content 
of  ether  extract,  to  give  significant  averages.    2Weighted  average. 


156 


BULLETIN  No.  317 


[December, 


1),  the  fat  in  the  bones  was  not  greatly  if  at  all  lower  than  that  of 
the  check  sheep  (see  Table  15),  but  for  the  other  two  sheep,  the  skele- 
ton also  was  largely  depleted  of  fat.  For  these  two  sheep  (Nos.  4 
and  5)  the  fat  content  of  the  flesh  and  offal  samples  was  lower  than 
that  for  the  other  sheep.  The  results  suggest  that,  in  undernutrition, 
the  skeletal  fat  is  the  last  to  be  drawn  upon.  The  wool  contained 
more  moisture,  less  protein,  but  only  slightly  less  fat  than  the  wool  of 
the  check  sheep. 

Growth  of  Wool  by  Sheep  on  a  Submaintenance  Ration.  For  the 
five  sheep  that  were  slaughtered  and  analyzed  after  210  to  227  days 
of  feeding,  it  is  possible  to  make  more  or  less  satisfactory  estimates 
of  the  amount  of  protein  and  energy  used  daily  for  the  growth  of 
wool.  These  estimates  were  made  on  the  assumption  that  the  wool 
was  shorn  to  an  equal  length  in  the  case  of  the  check  sheep  and  of 
the  surviving  sheep,  and  that  the  latter,  at  the  beginning  of  the  feed- 
ing period  on  February  22  had  on  their  backs  as  much  protein  and 
energy  in  their  wool  in  proportion  to  live  weight  as  did  the  check 
sheep.  These  amounts  of  protein  and  energy  were  subtracted  from 
the  sums  of  the  amounts  shorn  from  each  sheep  on  June  2  and  just 
previous  to  slaughter  to  get  the  amounts  added  during  the  feeding 
period.  Dividing  the  differences  by  the  numbers  of  days  of  feeding 
and  by  the  average  weights  of  the  sheep1  gave  the  daily  additions 
per  1,000  pounds  body  weight.  The  results  of  these  calculations  are 
given  in  Table  25. 

TABLE  25. — ESTIMATES  OF  DAILY  STORAGE  OF  PROTEIN  AND  ENERGY 
IN  WOOL  OF  SURVIVING  SHEEP 


Sheep  No. 

Storage  per  day 

Storage  per  day  per  1000  pounds 
body  weight 

Crude  protein 

Gross  energy 

Crude  protein 

Gross  energy 

11    . 

grams 
2.95 
4.14 
5.24 
5.95 
3.57 
4.37 

cals. 
31.7 
44.1 
54.6 
58.7 
37.6 
45.3 

grams 
39.9 
59.4 
70.8 
86.6 
48.5 
61.0 

cals. 
428 
633 
738 
854 
oil 
633 

33  

1  

4    . 

5  

Average  

Altho  these  sheep  were  losing  weight  steadily  at  an  average  rate 
of  .05  to  .10  pound  per  day,  and  were  in  almost  continuous  negative 
nitrogen  balance,  they  were  storing  daily  in  the  wool  an  average  of 
4.37  grams  of  protein  and  45.3  calories  of  gross  energy.  Per  1,000 
pounds  live  (unshorn)  weight,  these  values  become  61.0  grams,  or 
.135  pound,  of  protein  and  633  calories  of  gross  energy.  In  a  previous 

'In  getting  the  average  weights,  the  weekly  weights  after  June  2  were  each 
increased  by  the  weight  of  wool  removed  at  that  date.  The  weights  thus  ob- 
tained represent  the  sheep  unshorn  from  the  beginning  of  the  experiment  to 
the  date  of  slaughter. 


1928} 


ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOR  SHEEP 


157 


investigation1  of  sheep  of  approximately  the  same  initial  weight  re- 
ceiving alfalfa  hay  alone  in  amounts  sufficient  to  support  considerable 
increase  in  weight,  the  wool  stored  daily  per  1,000  pounds  body  weight 
contained  on  an  average  .149  pound  of  protein  and  566  calorics  of 
gross  energy.  Armsby2  has  computed  the  average  daily  growth  of 
wool  to  contain  .135  pound  of  protein  per  1,000  pounds  live  weight, 
It  is  a  remarkable  demonstration  of  the  independence  of  wool  growth 
and  of  food  intake  that  the  sheep  in  this  experiment,  losing  energy 
and  nitrogen  continuously  and  in  considerable  amounts  daily  from 
their  bodies,  should  store  energy  and  nitrogen  in  their  wool  at  an  ap- 
proximately normal  rate.  Joseph3  has  shown  the  same  independence 
of  wool  growth  and  nutrition,  tho  in  a  less  striking  way. 

Comparison  of  Composition  of  Tissues  From  Well-Fed  and  From 
Emaciated  Sheep.  It  is  of  great  interest  to  compare  the  composition 
on  the  fat-free,  or  "protoplasmic,"  basis  of  the  surviving  emaciated 
sheep  with  that  of  the  well-fed  check  sheep.  Such  a  comparison  is 
afforded  bv  the  calculations  contained  in  Table  26. 


TABLE  26. — PERCENTAGE  COMPOSITION,  ox  FAT-FREE  BASIS,  OF  SAMPLES  FROM 
CHECK  SHEEP  (WELL-FED)  AND  SURVIVING  SHEEP  (EMACIATED) 


Sample 

Moisture 

Crude  protein 

Ash 

Ratio  of  protein 
to  moisture 

Flesh  sample 
Well-fed  sheep  
Emaciated  sheep..  . 

72.90 
79.49 

22.95 
19.25 

1.18 
1.10 

1:3.18 
1:4.13 

Bone  sample 
Well-fed  sheep  
Emaciated  sheep1.. 

48.48 
53.34 

26.46 
22.00 

23.30 
23.26 

1:1.83 
1:2.42 

Offal  sample 
Well-fed  sheep  
Emaciated  sheep..  . 

78.84 
80.53 

18.91 
18.20 

1.16 
1.43 

1:4.17 
1:4.42 

'Includes  only  the  samples  of  Sheep  11,  33,  and  1.  The  fat-poor  bones  of  Sheep  4  and  5  showed 
much  wider  ratios  of  protein  to  moisture,  i.e.,  1  to  3.44  and  1  to  4.53  respectively.  The  moisture  in 
these  bones  on  the  fat-free  basis  was  63.97  and  70. 18  percent  respectively. 

Evidently  emaciation  has  increased  the  moisture  content  of  all 
tissue  samples  above  that  of  the  well-nourished  tissues.  This  is  in 
agreement  with  the  findings  of  Hoagland  and  Powick4  in  regard  to 
emaciated  cattle.  These  investigators  found  that  the  flesh  of  ema- 
ciated cattle  generally  showed  a  ratio  of  protein  to  moisture  of  1  to 
4  or  more,  while  in  well-fed  cattle  the  ratio  was  much  narrower.  In 

'Mitchell.  H.  H..  Kammlade,  W.  G.,  and  Hamilton,  T.  S.  A  technical  study 
of  the  maintenance  and  fattening  of  sheep  and  their  utilization  of  alfalfa  hay. 
111.  Agr.  Exp.  Sta.  Bui.  283,  245.  1926. 

zArmsby.  H.  P.     The  nutrition  of  farm  animals,  327.     Macmillan.     1917. 

Moseph,  W.  E.  Effect  of  feeding  and  management  of  sheep  on  the  tensile 
strength  and  elasticity  of  wool.  Jour.  Agr.  Res.  33,  1073.  1926. 

4Hoagland,  R.,  and  Powick.  W.  C.  A  chemical  study  of  the  flesh  of 
emaciated  cattle.  Jour.  Agr.  Res.  31,  1001.  1925. 


158 


BULLETIN  No.  317 


[December, 


the  emaciated  sheep  of  this  experiment  the  ratio  of  protein  to  moisture 
in  the  flesh  samples  averaged  1  to  4.13,  while  that  of  the  well-fed  sheep 
averaged  1  to  3.18.  Among  the  other  two  samples  the  ratio  shows 
the  same  tendency  to  widen  as  a  result  of  undernutrition. 

Loss  of  Body  Constituents  During  Feeding  Period.  From  the 
weights  of  samples  and  their  chemical  composition,  the  percentage 
composition  of  the  entire  carcasses  of  the  surviving  sheep  was  calcu- 
lated, with  the  results  given  in  Table  27.  The  great  emaciation  of 
these  sheep,  particularly  Nos.  4  and  5,  is  clearly  shown  by  these 
figures. 

TABLE  27. — PERCENTAGE  COMPOSITION  AND  GROSS  ENERGY 
CONTENT  OF  SURVIVING  SHEEP 


Sheep  No. 

Live  or 
empty 
weight 

Dry 
substance 

Crude 
protein 

Ether 
extract 

Ash 

Gross 
energy 
per  gm. 

On  basis  of  live  weight 


11  

23.80 

26.41 

14.80 

6.73 

4.42 

sm.  cals. 
1  476 

3        .      . 

22  06 

28  13 

15  63 

7  23 

4  45 

1  560 

1  

25  66 

23  19 

14  20 

4.78 

3.82 

1  286 

4  

22.38 

17.77 

12.77 

1.44 

3.66 

861 

5  

25.95 

18.47 

12.44 

2.79 

3.31 

966 

On  basis  of  empty  weight 


11  

19.63 

32.02 

17.95 

8.16 

5.36 

1  790 

33  

IS.  78 

33.04 

18.36 

8  .  50 

5.23 

1  832 

1   

19  SS 

29  93 

IS  32 

6  17 

4  93 

1  659 

4  

16.22 

24  53 

17.61 

1.98 

5.05 

1  194 

5  

19.43 

24.66 

16.62 

3.72 

4.42 

1  290 

Assuming  that  the  surviving  sheep  possessed  the  same  composition 
on  March  1  as  the  check  sheep,  killed  on  February  23,  it  is  possible 
to  make  approximate  estimates  of  their  changes  in  composition  during 
the  entire  feeding  period  of  212  to  227  days.  They  lost  an  average 
of  20.4  percent  of  their  initial  body  weight,  35.9  percent  of  their  initial 
content  of  dry  matter,  71.2  percent  of  their  initial  content  of  fat,  47.7 
percent  of  their  initial  content  of  gross  energy,  but  only  6.6  percent 
of  their  initial  content  of  protein.  In  making  these  estimates  the  nu- 
trients and  energy  contained  in  the  wool  sheared  on  June  2  have  been 
added  to  those  found  at  slaughter.  The  discrepancy  between  the  per- 
centage loss  in  body  weight,  and  in  dry  matter  evidently  is  due  to 
only  a  small  loss  in  water  which  averaged  only  9.2  percent. 

The  ash  content  of  the  sheep  increased  somewhat  when  the  wool 
is  considered,  but  the  ash  of  wool,  being  so  largely  dirt,  is  of  little  sig- 
nificance, altho  it  is  an  important  factor  in  such  calculations.  Thus, 
in  the  check  sheep,  the  ash  of  the  wool  shorn  at  slaughter  made  up 
an  average  of  25.6  percent  of  the  ash  of  the  entire  carcass.  Disre- 
garding the  wool,  therefore,  it  appears  that  slight  losses  occurred  from 
the  bodies  of  the  sheep,  averaging  9.2  percent. 


1928]  ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOR  SHEEP  159 

The  losses  of  constituents  from  the  sheep  carcasses  expressed  as 
percentages  of  the  losses  in  live  weight,  averaged  24.8  for  water,  4.6 
for  protein,  and  72.3  for  fat.  These  may  be  considered  to  represent 
the  average  percentage  composition  of  the  losses  in  weight.  The 
average  loss  contained  3.05  therms  of  gross  energy  per  pound.  The 
daily  loss  in  energy  averaged  217  calories  for  these  five  sheep.  This 
is  a  measure  of  the  daily  deficiency  in  energy  of  the  ration  fed. 

Feed  Consumption  and  Its  Content  of  Metabolizable  Energy.  The 
average  results  of  the  feeding  experiment  relative  to  losses  in  weight 
and  daily  consumption  of  feed  and  metabolizable  energy  in  the  two 
periods  are  summarized  in  convenient  form  in  Table  28.  In  Period 
I  the  average  daily  losses  in  weight  are  obtained  by  taking  the  initial 
weight  as  the  average  of  the  weights  on  March  1.  8,  and  15,  for  the 
timothy-hay  group,  and  as  the  average  of  the  weights  on  March  22. 
29.  and  April  2,  for  the  alfalfa-hay  group,  and  by  taking  the  final 
weight  in  both  groups  as  the  average  of  the  weights  on  June  14,  21, 
and  28  plus  the  weights  of  wool  removed  on  June  2.  The  calculations 
of  Period  II  relate  only  to  those  sheep  that  survived  into  September. 
For  the  calculation  of  average  daily  losses  in  weight  during  this 
period  the  initial  weight  is  taken  as  the  average  of  the  weights  of 
June  14  and  21.  and  the  final  weight  as  the  average  of  the  last  two 
weights  secured. 

In  Period  I  the  average  daily  loss  in  weight  was  practically  the 
same  for  the  two  groups  of  sheep,  tho  there  were  large  variations  in 
this  respect  within  each  group.  The  daily  intake  of  roughage  as  well 
as  of  oil  meal  averaged  slightly  less  for  the  timothy-hay  group  than 
for  the  alfalfa-hay  group. 

The  metabolizable  energy  intake  of  each  sheep  was  calculated 
from  its  daily  intake  of  gross  energy  and  the  percentage  metabolizabil- 
ity  of  the  gross  energy  of  its  feed  as  determined  in  the  metabolism 
experiment  of  the  same  period  (see  Table  21 1.  The  average  intake  of 
metabolizable  energy  per  day  was  considerably  greater  for  the  sheep 
consuming  alfalfa  hay  than  for  those  consuming  timothy  hay,  averag- 
ing 820  calories  as  compared  with  657  calories. 

The  metabolizable  energy  intake  of  each  sheep  has  been  com- 
puted to  a  standard  weight  of  100  pounds  by  two  methods.  In  the  first 
method  the  intake  of  metabolizable  energy  is  multiplied  by  the  ratio 
of  the  standard  weight,  100  pounds,  to  the  average  weight  of  the  sheep 
for  the  period.  In  the  second  method  it  is  multiplied  by  the  ratio  of 
these  two  weights,  each  raised  to  the  two-thirds  power.  Inasmuch 
as  the  surface  of  the  sheep  varies  approximately  with  the  two-thirds 
power  of  its  weight,  the  second  method  obtains  the  metabolizable 
energy  intake  for  a  100-pound  animal  in  accordance  with  the  ratio 
of  surfaces  rather  than  of  weights.  In  so  far  as  maintenance  energy 
requirements  consist  of  basal  metabolic  expenditures,  the  requirements 


160 


BULLETIN  No.  317 


[December, 


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1928]  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP  161 

of  animals  of  different  sizes  are  best  equated  and  compared  by  surface 
ratios;  but  in  so  far  as  they  consist  of  energy  expenditures  in  volun- 
tary muscular  activity,  differences  in  size  are  best  removed  by  weight 
ratios.  In  the  present  case  both  factors  are  involved  and  it  seems  im- 
possible to  decide  which  method  is  the  better. 

By  both  methods  of  computation,  the  timothy-hay  sheep  con- 
sumed about  20  percent  less  metabolizable  energy  than  the  alfalfa- 
hay  sheep  and  yet  their  loss  in  weight  was  no  greater.  The  conclusion 
seems  warranted,  therefore,  that  the  metabolizable  energy  of  the  timo- 
thy-hay ration  was  considerably  better  utilized,  i.e.,  possessed  a  higher 
percentage  availability,  than  the  metabolizable  energy  of  the  alfalfa- 
hay  ration. 

There  is  a  close  correlation  in  each  group  between  the  average 
loss  in  weight  and  the  average  intake  of  metabolizable  energy  per  100 
pounds  live  weight.  This  correlation  is  approximately  linear  in  char- 
acter and  may  be  expressed  by  the  equation  of  a  straight  line.  For 
the  two  sets  of  data  relating  to  the  energy  consumed  per  unit  of 
weight  and  for  the  two  groups  of  sheep,  the  equations  that  were  fitted 
to  the  data  best  by  the  method  of  least  squares  are: 

Alfalfa-hay  sheep 

Weight  ratio:        y  =   .438  -   .000317x  (1) 
Surface  ratio:        y  =   .506  -  .000419x  (2) 

Timothy-hay  sheep 

Weight  ratio:         y  =   .379  -   .000330z  (3) 
Surface  ratio:        y  =   .409  -   .000401z  (4) 

in  which  y  is  the  average  daily  loss  in  body  weight  in  pounds,  while  x 
is  the  average  daily  intake  of  metabolizable  energy  per  100  pounds 
body  weight  in  calories.  In  Table  29  the  sheep  in  each  group  are  ar- 
ranged in  the  order  of  decreasing  intakes  of  metabolizable  energy  per 
100  pounds  of  weight  for  comparison  with  the  actual  average  losses 
in  weight  and  those  computed  by  the  above  equations. 

By  the  use  of  equations  (1)  to  (4)  it  is  possible  to  compute  the 
metabolizable  energy  requirements  for  maintenance  of  body  weight 
by  solving  for  x  when  y  =  o.  For  the  alfalfa  sheep  these  estimated 
requirements  are  1,382  calories  per  100  pounds  body  weight,  using  the 
ratio  of  weights,  and  1,208  calories,  using  the  ratio  of  surfaces.  For 
the  timothy-hay  sheep  these  estimated  values  are  1,149  and  1,020 
calories  respectively.  These  values  should  not  be  confused  with  en- 
ergy requirements  for  energy  equilibrium,  since  immature  sheep,  such 
as  these  were,  would  probably  be  in  negative  energy  balance  even  tho 
the  weight  were  constant. 

The  data  of  Period  II  are  less  complete  than  those  of  Period  I 
because  of  the  death  of  three  of  the  alfalfa  sheep  shortly  after  the 
period  started.  The  daily  losses  averaged  somewhat  less  in  this  period 
than  in  the  preceding,  but  the  amounts  of  food  consumed  per  100 
pounds  weight  were  much  larger,  so  there  is  no  need  for  assuming  that 


162 


BULLETIN  No.  317 


[December, 


TABLE  29. — CORRELATION  OF  INTAKE  OF  METABOLIZABLE  ENERGY  AND 
AVERAGE  Loss  IN  WEIGHT  IN  PERIOD  I 


Sheep  No. 

Metabolizable  energy 
consumed  daily 

Average  losses  in  weight 

Actual 

Computed  by 

Weight  ratio 

Surface  ratio 

Equations 
1  or  3 

Equations 
2  or  4 

Alfalfa-hay  ration 


4  

Ibs. 
1  241 

cals. 
1  097 

Ibs. 
.054 

Ibs. 
.044 

Ibs. 
.047 

1  

1  153 

1  048 

.059 

.072 

.068 

5 

1  132 

1  026 

.089 

.078 

.077 

33  

1  094 

974 

.060 

.090 

.099 

9  

1  061 

966 

.117 

.101 

.102 

60 

985 

923 

133 

.125 

.120 

7  

967 

903 

.129 

.131 

.128 

Timothy-hay  ration 


8  

1  070 

940 

.029 

.026 

.032 

2  

1  013 

897 

.014 

.045 

.049 

3 

941 

844 

094 

.069 

.071 

10  

852 

HI   803 

098 

.098 

.087 

6  

727 

689 

.168 

.139 

.133 

11  

632 

582 

.145 

.171 

.176 

the  sheep  were  adjusting  themselves  to  a  lower  level  of  energy  expen- 
diture. In  fact  quite  the  reverse  is  indicated.  Of  the  three  alfalfa 
sheep  two  showed  smaller  losses  in  weight  than  in  the  preceding  period 
on  timothy  hay,  while  of  the  seven  timothy  sheep  four  showed  smaller 
losses  than  in  the  preceding  period  on  alfalfa  hay. 

The  average  daily  intake  of  feed  again  averaged  slightly  less 
for  the  timothy-hay  sheep  than  for  the  alfalfa-hay  sheep,  while  their 
intake  of  metabolizable  energy  was  considerably  less.  Per  100  pounds 
body  weight  the  metabolizable  energy  consumed  was  much  smaller  in 
amount  for  the  timothy  sheep  than  for  the  alfalfa  sheep. 

The  data  of  Period  II  therefore  confirm  those  of  Period  I  in 
indicating  a  greater  availability  of  the  metabolizable  energy  of  timo- 
thy hay  than  of  alfalfa  hay. 

On  June  15,  at  the  end  of  Period  I,  the  lightest  and  heaviest 
sheep  in  each  group  were  photographed  against  a  checkered  back- 
ground, with  the  results  pictured  in  Figs.  2  and  3.  The  alfalfa  sheep 
appear  to  be  in  somewhat  poorer  condition  than  the  timothy  sheep. 
In  early  August,  near  the  end  of  the  second  period,  group  pictures 
were  taken  of  four  sheep  from  each  lot  (see  Figs.  4  and  5).  These 
pictures  are  of  value  mainly  in  showing  the  wool  growth  that  has  oc- 
curred since  the  shearing  on  June  2. 

Since  the  losses  in  weight  of  the  alfalfa-hay  sheep  were  as  great 
as  those  of  the  timothy-hay  sheep,  it  seems  fair  to  assume  that,  thru- 
out  this  experiment,  their  energy  requirements  were  approximately  the 
same  per  unit  of  weight  or  surface.  Since  it  required  more  metaboliz- 
able energy  from  alfalfa  hay  than  from  timothy  hay  to  maintain  such 


1928} 


ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP 


163 


FIG.  2. — SHEEP  7  ABOVE  AND  SHEEP  4  BELOW  WERE  IN  LOT 

II  WHICH  RECEIVED  ALFALFA  HAY 

The  photographs  were  taken  on  June  15,  at  the  end 
of  Period  I.  No.  7  was  the  heaviest  sheep  and  No.  4  was 
the  lightest  in  the  alfalfa  hay  lot  at  this  time. 

equal  nutritive  states  in  sheep,  the  metabolizable  energy  of  timothy 
hay  must  therefore  be  considerably  better  utilized  in  the  body. 

Summary  of  the  Second  Experiment 

A  comparison  of  the  value  of  timothy  hay  and  alfalfa  hay  as 
sources  of  energy  has  been  made  in  feeding  experiments  on  sheep. 
Two  groups  of  yearling  western  wethers,  weighing  from  80  to  100 
pounds,  were  placed,  one  group  of  seven  sheep  on  a  ration  of  alfalfa 
hay  and  linseed  oil  meal  and  the  other  group  of  six  sheep  on  a  ration 


164 


BULLETIN  No.  317 


[December, 


FIG.  3. — SHEEP   10  ABOVE  AND  SHEEP  3  BELOW  WERE  IN 

Lor  I  WHICH  RECEIVED  THE  TIMOTHY  RATION 
The  photographs  were  taken  on  June  15,  at  the  end  of 
Period  I.    No.  10  was  the  heaviest  sheep  and  No.  3  was 
the  lightest  in  the  timothy-hay  lot  at  this  time. 

of  timothy  hay  and  linseed  oil  meal.  When  it  was  found  in  this  ex- 
periment, as  in  the  preceding  one,  that  the  timothy  hay  was  not  being 
consumed  in  amounts  sufficient  to  maintain  weight,  the  intake  of  al- 
falfa hay  by  the  other  group  was  likewise  restricted  so  that  the  loss 
in  weight  on  both  rations  was  approximately  the  same.  One  pound  of 
timothy  hay  per  head  daily  was  as  much  as  would  be  cleaned  up  con- 
sistently, and  one  pound  of  alfalfa  hay  daily  proved  to  be  equally 
efficient  in  preventing  loss  in  wreight,  so  this  amount  was  offered  daily 
thruout  the  experiment  to  all  sheep.  In  addition  each  sheep  received  .08 


1928]  ALFALFA,  CLOVER,  AND  TIMOTHY  HAY  FOR  SHEEP  165 

pound  of  linseed  oil  meal  daily  per  100  pounds  initial  live  weight. 
Salt  was  available  to  all  sheep  and  a  small  amount  (6  grams  per  head) 
of  steamed  bone  meal  was  given  to  the  sheep  on  the  timothy  ration. 
All  sheep  were  fed  individually. 

After  100  days  of  feeding  the  sheep  were  sheared.  At  about  this 
time  or  earlier  a  digestion  and  metabolism  experiment  was  run  upon 
each  sheep. 

At  the  end  of  112  days  of  feeding  the  rations  were  reversed,  those 
sheep  getting  alfalfa  hay  being  put  upon  timothy  hay.  and  vice  versa. 
This  second  period  lasted  112  days,  and  during  the  last  few  weeks 
digestion  and  metabolism  trials  were  made  upon  all  surviving  sheep. 

Six  sheep,  purchased  at  the  same  time  and  of  the  same  age,  breed- 
ing, and  condition  as  the  experimental  sheep,  were  slaughtered  at  the 
beginning  of  the  experiment  in  order  to  obtain  a  definite  idea  of  the 
initial  nutritive  condition  of  the  sheep  subsequently  fed.  On  the  live- 
weight  basis  they  were  found  to  contain,  on  an  average,  40.57  percent 
of  dry  matter,  16.32  percent  of  protein,  19.66  percent  of  fat,  3.52  per- 
cent of  ash,  and  .80  percent  of  calcium.  Their  "fill"  averaged  12.4 
percent  of  their  live  weight. 

The  wool  sheared  from  the  sheep  on  June  2  was  approximately 
the  same  in  amount  and  composition  for  the  timothy  and  for  the 
alfalfa  sheep. 

All  sheep  decreased  in  weight  from  the  beginning  to  the  end  of 
the  experiment.  The  losses  on  the  alfalfa  ration  were  of  the  same 
order  of  magnitude  as  those  on  the  timothy  ration,  and  in  each  period 
the  average  losses  were  very  nearly  the  same.  Evidently,  so  far  as 
may  be  judged  from  the  changes  in  weight  of  the  sheep,  one  pound  of 
the  alfalfa  hay  used  was  equal  in  energy  value  to  one  pound  of  the 
timothy  hay  used. 

The  digestion  trials,  however,  showed  conclusively  that  the  alfalfa 
ration  was  much  more  digestible  than  the  timothy  ration.  On  an  aver- 
age, the  dry  matter  of  the  timothy  ration  was  only  82  percent  as  di- 
gestible as  that  of  the  alfalfa  ration,  the  crude  protein  was  only  53 
percent  as  digestible,  and  the  nitrogen-free  extract  only  86  percent  as 
digestible.  The  digestibility  of  crude  fiber  and  ether  extract  was  not 
greatly  different  for  the  two  rations. 

For  the  same  weight  of  dry  matter  the  timothy-hay  ration  con- 
tained only  79  percent  as  much  metabolizable  energy  as  the  alfalfa- 
hay  ration.  An  average  of  45.5  percent  of  the  gross  energy  of  the  al- 
falfa ration  was  metabolizable,  while  only  36.9  percent  of  the  gross 
energy  of  the  timothy  ration  was  metabolizable. 

The  prevailing  nitrogen  balances  on  both  rations  were  negative, 
this  being  true  of  all  of  the  balances  obtained  on  the  timothy  ration. 
The  average  nitrogen  balance  was  -.15  gram  per  day  on  the  alfalfa 
ration  and  -1.47  grams  per  day  on  the  timothy  ration. 


166 


BULLETIN  No.  317 


[December, 


FIG.  4. — FOUR  OF  THE  SHEEP  OF  Lor  I,  PHOTOGRAPHED  EARLY 

IN  AUGUST  WHILE  ON  THE  ALFALFA  RATION 
The    picture    shows    the    active    growth    of    wool    since 
early  in  June,  on  the  markedly  submaintenance  ration. 

Five  of  the  six  sheep  on  the  alfalfa  ration  in  the  second  period 
died  of  undernutrition  before  the  termination  of  the  experiment,  while 
only  three  of  the  seven  sheep  on  the  timothy  ration  succumbed.  The 


FIG.  5. — FOUR  OF  THE  SHEEP  OF  LOT  II,  PHOTOGRAPHED  EARLY 

IN  AUGUST  WHILE  ON  THE  TIMOTHY-HAY  RATION 
This  photograph  shows  also  the  active  growth  of  wool  on 
a  submaintenance  ration. 


H.>,?S\  ALFALFA,  CLOVER.  AND  TIMOTHY  HAY  FOK  SHKKI-  167 

surviving  five  sheep  were  slaughtered  and  analyzed.  They  were  found 
to  be  in  an  extremely  emaciated  condition,  the  fat  stores  being  prac- 
tically depleted.  On  the  live-weight  basis  they  contained  an  average 
of  only  4.6  percent  of  fat. 

Three  of  the  five  sheep  still  retained  considerable  fat  in  their 
bones,  indicating  that  marrow  fat  is  among  the  last  of  the  fat  stores 
to  be  depleted  in  undernutrition.  The  two  sheep  showing  inconsider- 
able amounts  of  fat  in  the  bones  were  the  most  emaciated  of  the  group. 

The  withdrawal  of  fat  from  the  tissues  was  accompanied  by  an 
increase  in  moisture  on  the  fat-free  basis,  so  that  the  ratio  of  protein 
to  moisture,  particularly  in  the  muscles  and  in  the  bones,  was  greatly 
decreased  by  undernutrition. 

The  wool  sheared  from  these  sheep,  however,  did  not  differ  greatly 
in  composition  from  the  wool  of  the  check  sheep,  even  in  its  content 
of  fat.  Computations  of  the  rate  of  deposition  of  protein  and  energy 
in  the  wool  during  more  than  200  days  on  a  submaintenance  ration, 
indicated  that  it  was  normal  as  compared  with  similar  data  collected 
from  sheep  on  production  rations.  The  physical  characteristics  of  the 
wool  unfortunately  were  not  studied. 

During  this  protracted  period  of  normal  wool  growth  on  submain- 
tenance rations,  the  bodies  of  the  sheep  lost  71.2  percent  of  their  fat 
content.  47.7  percent  of  their  gross  energy  content,  but  only  6.6  per- 
cent of  their  protein  content. 

The  data  in  both  periods  proved  that,  for  apparently  equal  degrees 
of  undernutrition,  20  percent  less  metabolizable  energy  was  required 
in  the  timothy  ration  than  in  the  alfalfa  ration. 

Conclusions  of  the  Second  Experiment 

The  metabolizable  energy  of  timothy  hay  is  considerably  better 
utilized  in  the  maintenance  of  sheep  than  is  the  metabolizable  energy 
of  alfalfa  hay.  Since,  in  general,  the  metabolizable  energy  per  unit 
of  dry  matter  is  nearly  the  same  for  the  two  hays,  the  net  energy  con- 
tent of  timothy  hay  will  average  considerably  higher  than  that  of 
alfalfa  hay,  in  accordance  with  the  results  of  Armsby's  calorimetric 
experiments  on  steers. 

Undernutrition  withdraws  fat  from  the  muscular  and  glandular 
tissues  before  the  marrow  fat  is  affected.  The  withdrawal  of  fat  from 
all  tissues  is  accompanied  by  an  increase  in  the  ratio  of  protein  to 
moisture.  Neither  the  composition  of  the  wool,  however,  nor  its  chemi- 
cal growth  is  greatly  affected  by  undernutrition. 


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